Strength D is a terrible mechanic

Like this, except it's the game that suffers.

Formerly reserved for Apocalypse!, destroyer weapons, commonly known as Strength: D weapons, are now being integrated into regular 40k. While earlier 7th Ed Codicies used the D sparingly (Necrons, Orks) or not at all (Tyranids, Dark Eldar), Codex: Eldar appears to have brought D into the mainstream. And this is a problem.

What is S: D? If yo uare unfamilliar with this beast's current incarnation, it is quite (too) simple. After hitting with a S: D weapon (or indeed, since the advent of the Eldar codex, a D-weapon), roll a d6 instead of the roll to wound or penetrate.

1: Nothing happens. You know GW loves an arbitrary fail condition. Amusingly this does make S: D more prone to complete failure than S10 in some circumstances.
2 - 5: The target model loses d3 wounds or hull points, and additionally suffers a penetrating hit if applicable. If a model, the attack is treated as being S 10 for instant death purposes. Normal saves are allowed (subject to AP, invariably 2 at worst), but not Feel No Pain. You always feel the D.
6: The target model loses 6 + d6 wounds or hull points, and if somehow still standing, suffers the penetrating hit or instant death condition as above. No saves at all are allowed against this.

Already, you should see some big problems here. Firstly, the target's AV or T are barely considered, meaning that model's that pay points for increased durability are hit just as hard as models that don't. Secondly, it is subject to a lottery effect, where a roll of a 6 causes much more damage than any other result - in fact, on average the 6 inflicts more damage than the other results put together.

Fundamentally, S: D is a poor game mechanic. There are several reasons why, including those highlighted above, and some which are rooted in the narrative of the game's evolution. Many of these are related to underlying issues in the structure of the game that while not ideal, were workable by themselves. The combination of a kind of critical mass of these effects, plus the consequential introduction of a worse mechanic as a band-aid rather than an attempt to fix the structural issues themselves, has led to the current fuck up.

Units and models degrade in different ways
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Another part of the issue is apparent in the description of the effects. Note that vehicles sustain damage in a different way to models; this however is again a symptom. The underlying problem is that models sustain damage in a different way to units.

Consider a simple example, a Tactical Squad of Space Marines. 10 Space Marines. For each model in the unit, damage is a binary affair. He is either alive or dead. For the unit, however, the loss of one of the 10 members reduces its offensive output. If all 10 were armed with bolters, the reduction in capability would be proportionate to the number of models removed. Hence, the capabilities of the unit degrade in proportion to the damage that it suffers. 

This is not the case for individual models. While it is entirely appropriate for a game in 40k's scale for the individual Space Marine to have a binary approach to damage, this approach creates problems for models with 2 or more wounds. These models suffer no deleterious effects from damage that might on the face appear disastrous. A Wraithknight functions just as effectively with 1 wound as with 5. This means that single tough models have an advantage in wars of attrition against units.

To continue the previous example, suppose a unit of 10 Space Marines with bolters comes up against a single model with the same initial capabilities. Let's suppose that in the fashion of Centurions and Dreadknights, this is a monstrous agglomeration of 10 Space Marines, all bolted together like a bad Voltron parody. It shoots 10 bolters, but unlike the unit it is a single model with 10 wounds, equivalent to the squad's starting strength. Clearly, Voltron of Marines has a massive advantage over the unit he opposes. After each side has inflicted 5 wounds on the other, the unit returns fire with only 5 bolters. Voltron of Marines still has 10. He will win almost every time.

Given his manifest superiority, and adding his reduced vulnerability to blasts and templates (enduring only a single hit while a unit is likely to suffer multiple), we can naively expect that he will cost more points than the unit. Sure, his footprint is lower, and this will sometimes be a disadvantage, but will as often be advantageous, and he also benefits from different interations with the morale system. Since we expect a balanced game, we should expect Voltron of Marines to be more expensive than the equivalent units, reflecting the advantage of this differential degradation.


Vehicles exacerbate differential degradation
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To add to the confusion vehicles, which are typically single models, degrade in a different way again to models with an infantry profile. Unlike a single infantry models, a (non-superheavy, more on that later) vehicle does suffer adverse consequences to progressive damage, but unlike the unit of infantry models, the consequences are random and not proportional to the amount of damage inflicted. At least in 6th and 7th ed 40k the random damage consequences have taken a less important role due to the addition of 'hull points', a wound system for vehicles that makes their demise more predictable.

In previous editions from 2nd (technically 1st edition too, although only toward the end) through 5th, vehicle damage was entirely mediated through random consequential damage, completely at odds to the proportionate impairment suffered by units. As this system made vehicle degradation quite complex, and perhaps as a compensatory measure for the relative difficulty in damaging them at all, this system built in a criticality that could cause the vehicle to be instantly killed. It almost certainly owes as much to the aesthetic appeal of a single powerful shot causing a tank to explode to premeditated game design. This criticality is still with us in 7th ed as the 'Explodes!' result, although it is less important now that vehicles can be wrecked through gradual attrition.

It is worth noting here that models are also subject to a criticality in the form of 'Instant Death'. Unlike the case of vehicles though, this is strictly deterministic, and only in the case of the occasional weapon that inflicts instant death on the roll of a '6' is a similar random element encountered.

This random element in vehicle degradation and destruction makes it much more difficult to calculate an ideal point cost for them, as some of the time the vehicle will be certainly undercosted, and some of the time it will certainly be overcosted, due to the vicissitudes of random criticality and impairment.

So, there are now three different ways in which the player's pieces are affected by damage, depending on whether they happen to be models, units, or vehicles. Models do not degrade but rather suffer critical existence failure, units degrade in proportion with the damage suffered, and vehicles suffer from random degradation with the possibility of critical existence failure, but may equally be operating at full capacity even at death's door.


Superheavies are out of scale
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Considering the structure of the vehicle rules, it is not hard to see how superheavy vehicles posed a problem. First, random damage meant wildly unpredictable performance. A mighty vehicle could be effectively disabled by losing its most powerful weapon from the first damage it suffers, hardly an effective return for points, and much less so if it in fact explodes. So the damage table had to be modified to fit these invincible behemoths of the 41st millenium.

In retrospect, this should probably have been a warning sign. It made clear two things; firstly that the vehicle rules as written (and in fact the game rules as written) did not scale, and secondly that superheavies were beyond the scope of the scale 40k was written to accommodate. But the appeal of gargantuan tanks (and the accompanying kits) was inexorable, so some changes were made to paper over the cracks, rather than re-writing the affected rules. This led to a number of consequences.

The reimagining of the way superheavies interacted with vehicle damage retained the criticality, although it diminished the impact, and abolished the incremental impairment. This ensured that superheavies would fight at full efficacy until drained of their hull points, but would occasionally lose them more quickly due to the random criticality retained in the table (indeed as the only point of the table, since the other results do nothing). So, now they act like more of a model, and less of a vehicle, at least in the way they respond to damage - they don't, until they are dead.

While this lends a pleasing aesthetic of relentless and inexorable machines befitting the superheavy ethos, it impacts the game negatively. As we have seen, due to the way models are not impaired by damage, they must perforce cost more points than units of equivalent power or will otherwise be overpowered. Superheavies take this issue further, as they almost invariably have more hull points, sometimes many more, than the models these rules were originally designed for. This means that they can take a lot of punishment and keep on trucking at full efficacy, despite the units they face not being so lucky, and becoming less able to fight back with each casualty. Necessarily then, superheavies need to cost a lot of points to remain balanced.

It also means that within the 'natural order' of weapons with a numeric Stregnth value, there are few counters that can quickly stop a superheavy vehicle, as they must, like everyone else, chip away their hull points bit by bit.

This, however, was only one side of the superheavy issue. The other problem was that their weapons were out of scale.


Titan killing weapons and iron halos
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The resilience of a model, unit or vehicle in 40k is predicated on the scale of the action as it originally was, a platoon or so of infantry with some armoured support predominantly in the form of personnel carriers and the odd main battle tank. In this environment, it made sense that a heroic character should be hard to kill; he was likely to be the toughest guy on the field of battle as well as the aesthetic and dramatic focus of the action.

This resilience has typically taken the form of good saving throws, often invulnerable or othe fixed saves. This allowed criticalities such as instant death to remain (for those not lucky enough to surf the rising tide of 'Eternal Warriors'), but reduce their impact and protect the character from a lot of ills. While we've evolved from the days when every save could be taken one after the other, now, with multiple different sources of saves and avenues for rerolls plus 'not-a-save saves' like Feel No Pain, some characters have become extremely durable.

For a game of platoon to company level action this is not so bad. But again, the problem is simple: the mechanic does not scale.

Adding superheavies has, again, made this obvious. A vehicle dedicated to carrying the hugest gun it can, to destroy other superheavies and even titans, finds that its weapon is constrained by the rules for Stregnth, AP, and damage. Thus a Shadowsword's volcano cannon would knock off only a hull point or at best three from a target superheavy that it should by rights be able to immolate, and sees the same weapon bouncing off a mere Space Marine's iron halo. Why? Because the Strength scale was arbitrarily limited to 10, and the maximum values had already been assigned to what were, at that point in time, the biggest guns in the game.

Clearly, bigger guns than these would need a way to be more powerful than currently permitted. Again, rather than rework the system, a band-aid was introduced.

Sadly, this band-aid causes more problems than it solves.


Strength D doesn't care about you
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S: D was introduced to solve the problem of a bigger gun than allowed under the base 40k rules. In its current form, it allows weapons that are predominantly located on superheavy chassis to do multiple points of damage, unlike regular guns, and features a critical hit on a '6' that ignores saves, allowing it to bypass exceptionally tough characters.

But S: D doesn't care about your defensive stats. It strips your hull points or wounds on a 2+ and, if the '6' is rolled, chances are you are off the table, whether you are a gretchin or an Imperial Knight or a goddamn Baneblade.

We saw above how a model must be worth more than an equivalently capable unit by virtue of its resistance to degradation from damage. Now, we see a situation where a model is worse than a unit - because if that 6 is rolled for a single Space Marine, it makes no difference to the rest of the unit beyond the proportionate reduction from his inevitable death. When the 6 is rolled against Voltron of Marines, though, he can be taken of the board in one hit. For vehicles the problem is the same, except that the possibility of a random criticality is even higher than usual, owing to double jeopardy from both the normal damage and the destroyer table.

The implications are stark. Either the models, vehicles and other superheavys have had the chance of meeting - and failing to - a S: D weapon factored into their points cost, or they haven't. If they have, and assuming that miraculouly a satisfactory balance has been struck between the forces pulling the points value in opposite directions, then these powerful models will be undercosted against the armies that have no native S: D weapons. If they have not, then the rise of S: D on the 40k field will spell the end of powerful single models, as they will simply be too expensive for a model exposed to the critical vulnerability presented by S: D.


Strength D doesn't care about your friends
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Assuming the first case, that going forwards at least models are balanced against the expectation of meeting S: D, perhaps in large quantities, will the effects all wash out? Not necessarily.

Because S: D doesn't care about defensive statistics, tough models will be subject to diminishing returns. Very tough models will increasingly attract S: D, and therefore the prices will need to fall to keep them viable. However, as tough models are still resistent to everything else, this will make these tough models increasingly annoying to play against, as an increasing part of the opponent's army can be effectively marginalised by the very tough but aggressively costed units. Ultimately this is likely to lead to a degenerative arms race, where an escalation in relatively cheap tough units, costed so thanks to the expectation of facing S: D, require more S: D weapons to be brought to bear to effectively combat them. Armies could therefore drift into stagnant patterns, comprising of as many very tough cheap models as practicable, as many S: D weapons as possible, and some chaff to distract the opponent's S: D or tough creatures or claim objectives.

Codicies that are late to the S: D party or do not get an invitation will suffer moreso than the rest, first by enduring very tough , undercosted models and secondly by being pounded into the dirt by their D-toting opponents.


Wraithknight roulette
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What does a game in this brave new world of 40k look like? It looks like a competition to see who can roll more 6s soonest.

S: D by its nature does not care about your maneuver. It doesn't matter if you hit your foe in the side or rear. Sometimes it doesn't even mattter if the target is concealed. Removing these factors de-emphasises strategy in the game, which is already poorly articulated. A simple weapon that requires only basic target priority decisions does not make the game more skillful. And by allowing models with very high capacities for damage to be removed with one lucky roll, the risk:reward ratio is utterly skewed. This is compounded by the ability of models to ignore all but the last point of damage, meaning that an army that rolls no 6s can very quickly find itself in a situation very difficult to recover against an army that has had the good fortune to roll even just a few well timed 6s.

It's a far cry from the platoon level combat we used to have.


Degrade them
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Let's get speculative, and see if there are identifiable solutions to the problems raised above. After all, a well formulated problem contains the seeds of its own solution.

The first main problem is the difference in degradation experienced between models, units and vehicles. So why don't we standardise degradation in response to damage into something more proportionate?

A naive first attempt would be to say a vehicle or model can fire one less gun than normal per wound or hull point lost. This would be exactly in line with a unit that can no longer fire the weapons of its dead members, but still misses some points. For instance, most monstrous creatures and vehicles will run out of guns before running out of wounds or hull points. One gun tanks would be especially vulnberable. And besides, units rarely lose their best weapons first. In an average squad, 7 or 8 Space Marines with bolters will get killed before the more potent plasma or melta gun is removed.

So it seems that changing impairment in exact concordance with damage suffered is harder than it looks. Additionally, a system of modifiers keyed to the number of wounds or hull points lost or remaining could quickly become tedious. A solution that is simple enough to be understood viscerally and indicated on the board with a minimum of fuss would be much more likely to succeed. Most people don't want to have to solve algebraic equations to work out how many shots they have.

What to do then? I propose replacing the vehicle damage table with two simple conditions; damaged, and crippled. 'Damaged' would apply after a vehicle or monstrous creature suffered damage, and be represented by a -1 penalty to the WS, BS, and A characteristics. Guns will still shoot the same number of shots, but the reduction in accuracy will simulate the reduction in efficiency from normal.  'Crippled' would apply when wounds or hull points are reduced to half or less of their starting total, and be represented by halving WS, BS and A, rounding down. Thus, a Predator (3 HP) would shoot its weapons at BS 4 when undamaged, BS 3 when down to 2 HP, and BS 2 when on it's last hull point. Lelith would throw her 5 attacks at WS 9 at full health, 4 attacks at WS 8 on 2 wounds, and 3 attacks (2 + 1 for extra melee weapons) at WS 4 on her last wound. Yes, heroes will be less amazing, but instead of the narrative of the invincible hero reaping hordes of skulls, it will be the brave hero buying more time for their comrades by holding off the enemy while they bleed to death, or the chaos champion heroically pushing himself past mortal endurance for just one more skull, just one more... or indeed, the wounded 'hero' skulking off to hide behind some trees while they send their legions to the front to take their place.

The removal of the damage table also removes the possibility of critical existence failure, making vehicles much easier to price appropriately.


Scale them
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The next big problem is that of scale. We have seen that superheavies and their weapons cannot be adequately represented with 40k's classical range of S, T, and AV. So perhaps we need to expand the range. If a volcano cannon should be hitting twice as hard as a demolisher cannon, let's make it S 20.

As problem fixes often do, this presents new problems. Firstly the wound chart needs to be rewritten to accomodate the larger range (or a simple rule to accomodate an infinite range), and secondly instant death becomes readily achievable against a class of creature that never used to be vulnerable. Luckily, in these problems too there is opportunity.

To take the latter problem first, it makes sense to remove instant death entirely, given that we have already removed the criticality from vehicle damage. Now, however, there is no means for any weapon to deliver more than a single wound, which could lead to the incongruous situation of an imperial guard officer laughing off a volcano cannon. Clearly that is not ideal either. But perhaps this can be addressed in the 'to-wound' table itself.

Consider a new table that looks a little like this:

Chink in the armour: Even very tough creatures can sometimes be injured by lucky strikes. A 'to-wound' shown with an '&' indicates that to successfully wound, both (or all) dice rolls must be passed. For example, the required 'to-wound' score for S 4 vs T8 is '6+ & 3+'; this indicates that a 6 must be first be rolled, followed by a 3, to successfully cause a wound. A 'to-wound with 3 or more dice scores listed must have all scores satisfied. Abilities that allow a model to reroll wounds may be applied on any or all of these dice, but each dice may only be rerolled once.

Overpressure: Particularly powerful weapons can cause more severe damage than normal. A 'to-wound' shown with a '/' indicates that the attacker must roll more than one wound die. Each die that passes it's required wound score causes an additional wound that must be saved separately. For example, the required 'to-wound' score for S8 vs T4 is '2+/ 5+'. The attacker rolls two dice, one succeeds in causing a wound on a 2+, and the other on a 5+. If both wounds are caused the defender must save against both! Note that these wounds apply to models, not units, so if a Space Marine with one wound suffers two or more wounds, only that one Space Marine is removed as a casualty. Abilities that allow a model to reroll wounds may be applied on any or all of these dice, but each dice may only be rerolled once.


Hence, the 'to-wound table' now mediates damage taken based on the comparison of S to T. Characters are spared instant death and will often be more survivable to weapons in the range that previously destroyed them, which seems adequate recompense for degrading faster when they do take damage. Very tough creatures will still be difficult to injure, but the provision of a chance for any weapon to potentially, if improbably wound any creature allows armies that have lost their heavy weapons to not be put automatically out of the fight.

There is still provision for weapons that previously had special rules that conferring instant death to inflict extra damage, eg:

Lethal dose: if a 6 is rolled to wound, immediately roll an extra wound die. This will wound on the same score as was previously required, and must be saved separately. If a second 6 is rolled, repeat the procedure, but do not do so for a third 6.
The effect of these modifications, besides improving the scaling of the game and allowing a much broader range of model and unit capabilities, is also to smooth the probabilities involved. Swings of luck will still play a role, but models will be less vulnerable to criticalities, while still allowing powerful (and more expensive) weapons to have a proportionately greater effect.


Vehicles too
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The same principle can be applied to vehicle damage, too. Since the damage table has already been removed, there is no longer any need to differentiate between a glancing and a penetrating hit. Hence, the same chart could be used for both models or vehicles, de facto converting them to a Toughness value instead of an AV. It is also possible however to recast the table as a 'to-damage' table, using AV as an excuse to limit the dynamic range.

For example, perhaps we are quite happy that S3 weapons can't scratch AV 10, but want to retain the ability for conventional heavy weapons to have a chance against higher AV superheavies - albeit a low chance. So we put a cut-off point, below which the second dice is not available. Perhaps the gap between S7 and S8 demarcates the line at which the chink in the armour can come into effect, a line already familiar as the point at which a weapon becomes capable of damaging the heaviest tanks.

We can see here that now our hypothetical S20 volcano cannon has a good chance of inflicting 3 HP on an AV14 chassis - but has a better chance of inflicting that or more damage on more lightly armoured vehicles.

And this is the point. Weapons still get to be destructive, but the defensive statistics of the vehicle or model are no longer ignored.


Summary
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Bringing Strength D into the mainstream exposes the flaws in the mechanic. Like any problem however it can be viewed as an opportunity, and in this case it could act as the catalyst to fix some of the underlying problems that led to its introduction in the first place.

Resolving conflicts of scale and needless differences in response to damage would make 40k a more fun game, and make options, units and models easier to price appropriately, something that is in everyone's best interest.

Banish Strength D - replace it with an improved system.