I think games like Ni No Kuni did a fantastic job for a more modern rpg combat system. But, I still love the tactics turn based systems. It is going to come down execution, and frankly, square hasn't displayed they can do that. Take Tomb Raider. I don't mind QTEs, in fact, I enjoyed them in some games (Shenmue and God of War) and they were terrible in Tomb Raider.
I was someone who was a proponent for keeping the turn based battle system. Updating it was fine, but I like turn based. I'm not so fond of action based.
Thinking on it now, I'd still prefer something based off the old system. But, I do play and enjoy games with action-y type game play, like Star Ocean and the Tales games. So, making the game a sort of hybrid would still be in my tolerance range,
if done right (although I'd really prefer turn based).
But, discounting the 2 mmo's, I haven't particularly cared for a ff game since 10. With every release, the battle system is 1 step further away from anything I'd want to play. The characters become a bit more boring. And the story gets more sleep inducing with every iteration.
I'd like to think they could overhaul the game and make it better, but, I really don't trust them to make good decisions, truth be told. Even if there are changes to the story that could make the game better, wholesale changes to the battle system that would make long term fans, and new fans both happy....I'm guessing square will choose the exact opposite, and piss everyone off.
If the game has turn based combat (which we know it doesn't), I'd buy and love the game. If the game has a hyrbid turn based/action combat, something in the vein of tales or star ocean, I'd buy it and be satisfied. If they turn it into full blown action, with rpg trappings, I'll pass. It's pretty much that simple.