I dont always want to kill my enemy believe it or not. I think that all NPCs and creatures should run away when they get to a certain percent health (based on their confidence (which is set in the creation of each character)). This way if we get into a fight in town we are only charged with the fine for fighting, not murder. If im in a bar and I get into a fight, I want to just knock the guy out or get him to leave. And nothing with a brain stem is going to stay and fight you when they have 1 hp left.
Blackjack + fists as knockout weapons. Rendered obsolete by all heavy armour and some high level light armour (although light armour can be counteracted with high one handed/hand to hand levels). Unconscious NPCs don't even need to act differently once down to dead NPCs. It's a peace of mind thing.
...no i can see some enemies fleeing on occasion but if everything took off when it was losing, the entire game would become an annoying chore of tag with swords