This idea has been thought to death, seriously, I'm sure everyone has thought this idea up before and thought to themselves "Hur hur, I bet nobody thought of this before!". I'm sure that in certain games it could work (Survival Horror, extreme-to-the-E realistic shooters), but the main reason why we have games where you can take 15 bullets to the chest and survive is because gamers want to spend less time spazzing out and scrounging for health packs and do, you know, more game-y parts of the damn game.
Now, look, I'm not trying to insult you here. I'm sure in certain games that this system would work, and I would love to see some games employ that method (including the blood-loss and after-shock, not just limb-based damage). But everybody has thought of this idea already. Health systems haven't really evolved because they're simple enough as is, there's not much you can improve upon the mechanic that tells you if you're going to die or not.
Now, look, I'm not trying to insult you here. I'm sure in certain games that this system would work, and I would love to see some games employ that method (including the blood-loss and after-shock, not just limb-based damage). But everybody has thought of this idea already. Health systems haven't really evolved because they're simple enough as is, there's not much you can improve upon the mechanic that tells you if you're going to die or not.