Hussar
Legend
I'd argue that it's not HP specifically that's the problem. You certainly can have sim systems that grant numerical values to various elements (whether a Body/Stamina divide system, or a HP location system like in Battletech or I'm sure there are a thousand others). It's that in D&D, HP loss doesn't tell you anything. The mechanics are not tied to any information other than the loss of HP. It's a number that goes up as you level up (again, not really simulating anything other than D&D itself - the idea that killing orcs makes us harder to kill is pure gamism) but never actually informs anything that happens in the game.As others noted, RQ has hit points. IIRC C&S has levels (my books were destroyed a few years ago by a flood). Both have been cited as simulationist.
HP in combination with other systems certainly can tell us more about what is happening in the fiction as it happens. As I mentioned upthread, Battletech uses a Hit Location System with specific results for attacks. An attack that does not penetrate armor only does armor damage, and the value of the armor of that location is decreased after a hit. Missile barrage attacks are grouped into smaller sub-groups, with each subgroup striking a different location, simulating the idea of a barrage, rather than a concentrated attack like you would get from an directed energy weapon. Once you get through the armor at that location, you begin damaging internal systems in that location, potentially destroying weapons or even limbs, which again, have additional effects.
IOW, from beginning to end, I can tell you exactly what happened to that Mech and why it's now a smoking ruin on the battlefield.
THAT'S what a simulation system looks like. It seems to me that people who are arguing for D&D as a sim system haven't actually played a simulationist system before. The truly funny thing is, if you were to suggest D&D as a sim system to people who exclusively play simulation games, they'd giggle at you. The only people who think that D&D is a sim game are people who play D&D and don't play sim games.