Asymmetry in D&D design

From a design standpoint, one is likely to be immediately struck by the different way D&D handles offense and defense. Offense is a d20 check to overcome a target number. Certain defenses (armor, Dex, and so forth) affect your defensive score, but it's notable from an out-of-game viewpoint that skill affects your ability to hit but not to defend. Except for a handful of abilities, your defense raises slowly except for equipment and magic-related increases. Even the monk sees only a +5 dodge bonus over 20 levels, while gaining +15 to hit.

Hit points are an excellent mechanic for a simple reason; they give heroic characters and formidable monsters staying power. Rather than dodge-dodge-dead, combat allows for some level of attrition. Combat attrition is fun; we love it in computer games, we love it in climactic action hero battles, we love it in unrealistic sword fights. And we love it in RPGs. At the same time, we also love genuine danger, which is probably the main impetus for the popularity of the critical hit in its various forms in various games, from GURPS to Warhammer Fantasy to D&D 3e.

True20 removes hit points and ties offense and defense to a single combat bonus, removing the traditional D&D coupling. While experienced characters can gain some durability, the emphasis is on not being hit. Attrition takes a different form, through wound levels and the use of conviction points and special abilities.

This has important implications for the designer of a D&D variant (or a new edition). If you maintain an even ratio of attack and defense, combats will get longer and become more predictable as hit points increase unless damage increases proportionally. This is the dreaded "grind." If you look at Star Wars Saga, you see large hit point totals, multiple heal mechanics, a defense bonus that raises faster than the attack bonus, and hit points increase at a much faster pace than damage. As a result, it takes Destiny points to explain the confrontation with Darth Sidious in Revenge of the Sith; it simply not possible for even the Dark Lord to offhandedly kill several lesser Jedi Knights in a round or two. Whether intentionally or not, SW Saga leads to very grindy combats if you depend on hit point attrition.

In D&D, certain effects stand outside the hit point track. For instance, being stunned puts you out of action and can lead to lots of damage, quickly. Even a well-healed character can be stunned. Similarly, in SW Saga, the condition track can take a powerful character down long before hit points in many cases. D&D 4e has moved toward more attrition effects, less "save-or-die." The result? Slow combats. Now being paralyzed or whatever is just another hit point track.

If you wanted to design a D&D variant that featured a lightly armored character, you would have to set aside the idea of a very high Armor Class. Instead, looking at the monk, you would see that small bonuses lead to hit points depleting more slowly. What a character needs in D&D to be a resilient fencer or acrobatic kung fu artist is hit points. To get the right flavor, abilities should compensate for a lack of armor. For instance, the 3.5 monk's Wis bonus to AC and +1 AC every five levels compensates somewhat for a lack of armor and shield.

4e is something of an evolution. In 3.5 it was not clear what a monk's "role" was. Not to pigeonhole the class, but simply to state some way to play a monk that would be especially effective. A monk in 3.5 does not inflict heavy damage, nor do they have the AC or hit points to go toe to toe. They lack many utility abilities. Fundamentally, they have defensive advantages, in terms of mobility, saves, and immunities.

If you think back to the fundamental asymmetry in D&D, it should be clear that the 3.5 monk is unsuited for melee combat. They have a medium BAB, too slow for fighting dragons; they have a modest AC, too low for effective tanking; they have modest hit points, too low for engaging melee characters. Their advantages are all situational. Their main defenses are versus saving throw-related effects, and their best tricks are save-based or involve inflicting a status (such as prone or disarmed). Clearly, the monk either needs improved combat capabilities, or they should have a wider variety of skills that supplement their abilities. If they blend the fighter archetype with a sort of tumbling rogue, it has to be recognized that they have neither the fighter's arms and armor nor the rogues sneak attack bonus.

The difference between a fighter and a wizard is not most importantly about one being magical and the other not. The fighter can take a lot of damage but dish out only modest amounts, while the wizard is the reverse. This defines their combat roles.

The importance of this assymetry becomes apparent when fighting a powerful opponent. A character's defenses matter far less against a blue dragon than their ability to withstand an attack, either through hit points or immunities. A fighter's skill is apparent when he is grappled and bitten and yet survives. Dragons, in D&D, are defined as enemies of a certain threshold. A lesser fighter might pierce their scales with luck, but lasting minute after minute, delivering enough telling blows to finish the beast, is reserved for a true hero.

While 3.5 is too patchy in how it addresses the nature of D&D combat, which is to overcome an opponent through attrition or attacking an Achilles' heel, 4e is too consistently stacked in favor of attrition and relatively safe combat. Even minions usually take a respectable roll to take out.

In designing a D&D variant, it is important to consider whether you prefer the attrition model, as in D&D proper, or a sort of escalating gamble, as in True20. Removing the wagering element would make something unrecognizable as D&D. For instance, in GURPS it is possible to run a game such that two swordsmen might trade blows and end the fight in seconds, or an instant. In D&D, this can occur only between very low level opponents, and then the question is not skill but initiative. In D&D, you do not simply look at the tactical situation as it stands. You are taking into account what has transpired, and deciding whether and how to proceed.