I've just finished it for a second time, and I love it. Feels like it's a return to the snes games, mixed with Game of Thrones and completely new gameplay.
It's been too long since I played 15 to remember the distinction. It's action based, so maybe closer to 7 remake. I think much more action based than either though, there are combos and no ATB bars. The demo is the prologue of the game though so no idea how it develops