I have recently seen debate about how D&D handles armor. The thrust of the naysayer argument is that the armor class system of D&D is unrealistic because it conflates wearing better armor with being harder to hit.
They argue that heavier armor would have the opposite effect in that it would provide more protection, but the wearer would be easier to hit because they would be slower.
They suggest that armor should instead have something like a Soak value, where the attack roll is not affected by what armor is being worn (or at an inverse of what it is now), but once the total damage is determined, the armor’s Soak value then reduces the incoming damage, commensurate to how protective the armor is.
This isn’t a bad argument. The problem lies in the fact that the argument fails to understand what the current Armor Class system encompasses. It all comes down to terminology.
In D&D, we often use the terms “hit” and “miss” when we should really say “does damage” or “doesn’t do damage.” When a target has an AC of 18 and an attacker rolls a 15, it doesn’t mean the attack was a complete whiff. Rather, it means it simply didn’t do damage–perhaps it was a glancing blow, parried, or deflected with a shield. In this way, a higher AC doesn’t mean a target is harder to hit, it simply means it is harder to damage, just as one would expect with better armor. This also means there is already a “soak” value of the armor baked into the roll.
Given the choice between two methods that accomplish the same thing, I’ll always pick the simpler of the two. I’ll take less rolls and less math paired with proper DM narration to keep the focus where it belongs–on the story.