I still don't know why developers don't use the segmented health as seen in Far Cry 2, Resistance: Fall of Man, and Chronicles of Riddick.
Your health bar is divided into smaller bars, and each bar regenerates, but only until that bar is full, and never more than that.
Basically, if there's some health left in the bar, the bar will regenerate, but it will only regenerate that bar. That means developers know players will always have at least one bar of health, and can plan accordingly.
Or you could go the Brothers in Arms route and if a player hits a checkpoint with no health/ammo left and they die a few times, they get the option to restart at the checkpoint with full health and ammo. Since, you know, even though war isn't fair, a game should be. And thats the actual message when Brothers in Arms gives you the option. In Road to Hill 30 at least.