How about if placing a bounty on someone not only cost you tickets, but PvP rating? That way people trying to climb the ladder have an incentive to retaliate themselves instead of placing a bounty, and it doesn't disadvantage levelers at all. Perhpas PvP "cost" could be proportional to ticket cost. BUT, this would only be workable if you could always do a retaliatory attack on anyone who attacked you, perhaps instead of placing a bounty. Which is also a good idea, from what some PvPers have told me.
Not a bad idea, but you're going to have a ton of issues whenever the ladder resets, where people can work around the system. Also the PvP "cost" has to be huge, otherwise it can be used to get an advantage, just like it has this far (eg. lower your own rating to take more from the opponent)