Here's another idea, how about someone makes it so (in a mod) all those weak heroes have second forms they turn into when they die? (like Dai Oni into ghost-thingeys)
Make it so the secondary form represents them as unconcious (they can't attack or move, have much decreased stats etc.), that would give them a chance to survive a battle where they take one critical hit, and I think its quite thematic (there are several instances in books where the hero is knocked unconcious and then reawakens to see the results of the battle).
Only in a mod though, of course
