I agree there should be improvements to PvP. My LS does ballista/brenner just for fun on occasion to test our skill but we never use the actual "game" they have built into them. Its fun to just enter a completely deserted zone and kill your friends without consequence but it could be made a lot better.
A reward system of exp or gil would be exploited to no end sadly so that's not such a great idea imo but they could at least give us more options for it.