Perhaps it's just wishful thinking, but this does sort of look turn based.
I mean, take a look at the battle menu on the left hand side - The most obvious one that stands out is the 'defend' button which is pretty much an indication that it is somewhat turn based, because usually it's a simple button prompt for defend, or roll or whatever. Can you imagine the sheer annoyance of navigating the menu to 'defend' at just the right moment before you get attacked?

Also, it would just be hugely annoying navigating a menu in real time to find a Potion, Eye Drops or scrolling down your magic list for Quake 3 or whatever all the while you're getting screwed from the enemies.

The video up top wont load but if you look at 1:18 on the official video it looks like you're still fighting as Cloud, as he runs over to the guy behind Barret and attacks. These camera angles and lack of ''follow' would suggest there is no free movement here, just commands. Even if you're not fighting as Cloud at that moment, but rather Barret, the camera angles would still suggest turn based because the camera is facing Barret while he's attacking.

You also have a moving bar under their names too, which look similar to a XIII style, IE each attack takes up a certain amount of the bar so you can do combos perhaps, so again, suggests turn based.

So far. this game, to me, looks amazing and while it's pure speculation / theory, from what i see, this game looks more turn based than action.