The stamina bar can be more "realistic," like more breath? Or, even though this will take awhile, make it so when you a "teen" or "kid" you have less, or if your guy/girl is just plain fat, give them like small amounts. Just sayin'.
That is a cool idea... I also think that if people have low enough health they should move at slower speeds. These could add so many cool scenes :D
Like if two guys are running away from a horde and one shoots the other's leg so he can escape, the guy who was shot would move slowly and he'd get eaten while the other guy escaped XD Shane and Otis
But that would require the shot man not shooting the shooter (shooty shoot shoot)
So if you get shot you can't use weapons :o
Or people can just be good roleplayers!