Depends on how it is implemented. Blitzball on FFX was quite fun but also repetitive and boring after a while, if they implement it in here and allow your team composition to be of all human players, all npcs, or a mixture of both, with tournaments along the way, some nice rewards and maybe some ways for you to learn skills and improve your blitz game (like FFX had) it could be quite successful and played a lot.
Or not and it will sit in a corner like Verminion. I'd love if they try and implement it though, it's one of my favorite FF mini-games.