ExploderWizard
Hero
But that's for a unit of soldiers, generally. The unit breaks, and thus the entire group is out of the battle. Sure, many still live, but they get scattered and unable to regroup into any size capable of being a threat. If their side loses, they'll likely die trying to flee as the enemy sends cavalry/whatever to hunt down survivors. If their side wins, they can't go back; they'll likely get executed for leaving the battle. Similar to how in 3E, killing a swarm's hp doesn't kill all x thousand of the bugs, it just utterly scatters them.
This concept does not work so well on the individual level D&D deals with, IMO.
I agree. Morale works well as a group mechanic. Basic D&D got it right. Check morale for the group if things start heading rapidly towards defeat. At that point the victors can pursue the broken troops or end the engagement holding the field.
Individuals should decide if surrender or retreat is a viable option depending on thier intelligence, knowledge of the foe, and other factors.
The 4E movement rules did make it harder to retreat without getting whacked though.