I will have to reserve complete judgement until the game is out, but from what we know, and from what the developers have said, there are not going to be any gameplay changes.
What I was hoping for was a way to make the 100% completion in FFX-2 completely obtainable no matter what point of the game you are at. Or to at least make changes so that you know much easier where to obtain certain % before you go past the missable points. Getting 100% in X-2 is nigh-on impossible unless you follow a guide to a tee, and even then you have to really make sure you do stuff exactly.
I'm really disappointed that for something so hard to obtain without following a guide, they haven't made any changes to that. I really expected something relating to making achieving 100% in X-2 easier.
Again, will reserve complete judgement until the game's out, but they have said they aren't changing anything. Nothing I will lose sleep over, but disappointing all the same.