RPG damage systems are garbage. Games obsess about “realism” and then lose their minds when damage is calculated.
In the real world, stopping power looks like this. Therefore our “realistic” damage system that looks like this:
Roll 1d10. For each additional hit sustained, subtract 1. On a roll of 4 or less, you die. On a 5 or 6, you are incapacitated. On 7 or greater, you are injured.
This system assumes center-mass; head hits are usually lethal (1-9 on d10) and limb hits usually not (maybe 1-2). Also note that the above assumes a handgun; a rifle or shotgun is basically “8 or less and you die”.
No one wants to play that game, because combats will be over very quickly: a hail of bullets followed by a desperate need to get just about everyone still breathing to a trauma center.
We have no data about blasters and so forth, but we can presume that future weapons will be more lethal as time goes on.
Fantasy games have a problem, in that we don’t have much in the way of statistical data about swords and spears, the way we do for pistols and buckshot. We are also viewing data through a historical lens.
We don’t have any serious data about obvious things: just how effective was a crusader longsword against mail? Or arrows? How many hits could a person take? Could armor turn dozens of blows?
Guesses are all we have (although many are very well-educated). 2 great books on the subject, “On Killing” and “The Face Of Battle”, provide some insight. Our damage table of “struck my a medium weapon while wearing chain mail” probably looks something like this:
Roll 1d10. 1-3, you die. 4-7, you have a serious wound and are incapacitated. 8-10, you are injured.
Note that in both cases we take incapacitated to mean “unconscious, stunned, in shock, or otherwise unable to fight”. We define injured as alert and (possibly) able to fight back. Injuries will (obviously?) require treatment, and even if the fight ends the injured party might still pass out or die. Dead is still dead.
Also we have to deal with injury in a realistic way. In AD&D a creature can huge amounts of damage to a player, and the fix is relax at a convenient tavern for a period of time. A gunshot wound to the forearm can – and probably will – cause permanent nerve, muscle, or bone damage (likewise for the impact of a mace). The bones may mend, but will the hand ever again hold a weapon?
No one wants to play a game where sickness, injury, and being permanently crippled in the first play session are serious parts of the game (counter-example: the very strange Torchbearer). So what role (no pun intended) does serious realism actually play? How does it affect narrative vs grognard gaming?