Adding gear rewards specific to PvP on FFXI is a great reward for people who enjoy Ballista, and even Brenner (I guess). But as I mentioned before, adding general rewards that impact the game overall could invite players who would simply exploit it to reap easy treasure. The idea is a bit flawed. If there was a way where it could be inviting to players who aren't fond of Ballista, while making it challenging for them to get what they're after, it might get them to take it more seriously.

By exploitation, my biggest concern would be maybe 2+ people who take turns killing each other and scoring for the sake of building points to purchase rewards with Ballista points, or be instantly rewarded with items through a potential new idea that was brought up before. My solution would be to simply to take them both out! Anyone who has been there can figure out who is playing their part to benefit the team and who is there to screw around and feed the other team free wins.