Finished the demo
The Good
The battle system seems to be mildly interesting. I was at first disappointed by the lack of a proper party but switching between garbs is good enough for a fast paced combat system like this. Guarding seems like it'll have potential, however there were multiple times during the boss fight where I couldn't even see what was happening because of Blizzaga (or Blizzara? don't remember) taking up like 90% of the screen and covering the enemy. I saw that there were also different variations of the guard command, like the Dragoon having something like a counter. The demo ended just about then so no idea how it works. Might return later to try it properly. Generally speaking the game felt good to control and rather fluid. Oh, the music was also very nice.
The Bad
Dialogue and voice acting. Not that I expected anything stellar. It's still as bad as FFXIII and XIII-2 so no surprises there. And then there's of course the fact that it's still in the FFXIII world and that a bunch of unlikable characters are returning. It's probably unfair to rip a game for two things that are literally in its name but I just kept thinking throughout the demo how cool it would be if it was just a different game using the same combat system.
The Ugly
For a game where a big focus is on outfits this really is hit or miss. I looked them up on the FF Wiki and the range from cool to terrible and even downright embarrassing is simply staggering. I guess it doesn't help that Lightning has the body of a 12 year old with C-cup boobs and looks terrible in anything that doesn't hide that fact.
Garb spoilers: This is good.
This is not, and possibly NSFW.
In conclusion, I was pleasantly surprised by the combat system. It's hard to say how how the rest of the game will pan out and I won't hurry to buy it but I might give it a chance eventually.