Maybe the player character could just stay at the back out of the way and not fight? You get a little icon to represent the PC but you do not have to worry about him dying nether does he become some sort of uber fighter just to insure he stays alive.
Depending on how the Devs implement non fighters you could have say your PC at the back with the baggage train and the various non fighting camp followers. They would not do anything in terms of combat maybe a couple of passive bonuses to morale or some such.
The same could happen with enemies that you face, their leader sits at the back giving orders should you defeat them you can capture him, his followers and baggage train. You could then maybe recruit them or ransoms them back if they were say the son of a rich noble playing at war with his own mercenary company, or for bandits, orks and goblins hand them over to the authorities for bounties. Another element you could have is that say you defeat a vicious gang of bandits you then have to transport the leader back to a far off city to hand him over all the time being pursued by his gang.
