You are assuming level difference between the attacker and the bountied would give an advantage. It doesn't have to be that way. As long as the xp gained from attacking a player on the BB is reduced to a much lower xp gained(say10-20%) than from killing a game critter, the BB will continue as a deterrent while giving players PLAYING the game a slight xp gain.
This quote exemplifies the reason this idea should be implemented. Again, the developers need to do some developing!
I agree that XP should be lower than hunting, but how can you compare 10 hits of varying 10-100, to nearly 1000+ hits with lib kicking in, AL? If 1 hit = less than 1 monster kill that is not even worth implementing.
Why don't you leave the win of a bounty a flat rate so only the winner can get it.
Plus, what if you force-stopped leveling to sit at the end of a bracket? Those people sit with 60,000 stam overflowing, and don't want to accept any more XP. Is there an opt out setting?