More Ivalice, more political intriguey themes but better paced, more massive open world that can suddenly screw you over because holy crap! dragon, dem Moogles, more incredible voice acting, some form of the Gambit system, story-gameplay symbiosis but with a slightly better license board (e.g. Sphere Grid style), side quests, Hunts, and Balthier.

That's everything off the top of my head.