RMT bots (and non RMT bots) have a huge advantage, they can work constantly 24/7, if they tweaked the XP it may make people go out and mine up shards (I'd love to, I use too many too) but the bots have advantage in numbers too so can constantly undercut legitimate players.

The only true, real solution to removing RMT is by ensuring no one purchases gil, if the RMT make no money they move on. The solution SE has gone for is to make the current "best" gear dungeon drops, and below that CM grinding, but there are lazy people who may find they would rather dungeon than spend 30k gil on item X or Y, or maybe they went for the crafted 2 star gear and want material, instead of grinding up the gil they hit the RMT websites. The only real solution to that is to ban the people who buy gil forever and go after them with a passion as in banning them within 20 minutes of them buying gil.