Should characters die only when they run out of hit points? Or should the character be susceptible to death at any one moment by a well crafted hit? If your game doesn't use hit points, should they only die when they reach a predetermined amount of damage? For example three hits.
Most games that use wounds as damage tokens still can't easily allow for a single kill wound. So should there be a threat index? A level of damage that is significant above which the character dies? Is that the meaning of weapon damage or should there be another indicator? A damage effectiveness?
Death by RPG impact is pretty final, but there's a lot of room for discussion between taking a .45 to the heart and a 7.62 to the femoral artery and bleeding to death over the course of minutes.
Hit point systems that add hit points give characters a fighting chance during combat. It protects them from sudden death, extends their life expectancy and thus the game and enjoyment. But they bring forth other issues. Escalating power issues as weapons, spells and healing needs to escalate as the characters level up.
Personally I prefer systems which are closer to one hit and your dead. That promote character survival through skill and training. You can't die if you can't get hit. Characters can have about the same life expectancy as hit point systems with the added adrenaline rush for the player (and the excitement that brings). It also eliminates many of the drawbacks of having to deal with large hit point values.