I'm going to agree with those who said the ability to swim and blitzball, and also boats that you can actually ride on with rare monsters that you could fight if they spawn that would possibly award fun things like a glamor or vanity type drop. A new race would be interesting, but honestly I'd rather see an expansion of multiple endgame activities and a focus on keeping older content more relevant as well as finding ways to add in new content that won't lose relevance with the next big patch. It would be nice to have enough of a choice of endgame that lockouts wouldn't be so much of a thing.
