Based on everything I've seen of it, and it's a lot, they've remade just about every aspect of the game. The main difference is going to be that it makes sense for mobiles, so you can play it on the go. In other words, you know how the hotbars are 4 buttons when playing as scions? It'll probably be like that.

Based on the footage, it looks slightly better than what we have now in ARR, although to be fair they are working with a smaller resolution.

As I said in the other thread, if they give every person a house in the mobile version, it'll raise questions about the inability of Square Enix to do that in the regular version.