Will the dead benefit, or will weaker characters (and players) have to linger around the good players with their shield up and not take any risks at all? As a thrower I'd never try face off a charging cav because if I miss or just wound the horse I am so dead (which, by the way, makes it soooo much fun). Plus I'm gradually getting better at melee, but if every time I try to face a half ass decent player I'm gonna lose out on 3-4 minutes exp and gold I might just run, and never, ever get good at melee, just going for the opportunity kills.
I like the idea of bonuses for ability, but not in exp and gold. The guys getting all the kills have already mastered the fighting skills, plus probably have all +3 equipment already. It would be uber cool if they got titles of something like that that doesn't make them even better fighters yet. Then you wouldn't feel so bad when killed by a duke, but rightly disappointed in yourself if you're killed by a serf.