GUI

i dont know if GUI will look much different, it's probably gonna be some minor tweaks. for example if you're not in party; before your name still appears in party menu on left screen, which is unnecessary, so they might do away with that.
If they change the look, it will be new anyways i'm sure. i don't see why they would dump alpha UI, and reuse 1.0, or XI UI...that would make no sense at all.

With GCD i think macros will not be quite as useful as in 1.0.
Only reason to use it, is if you wanna be minimalistic, and not show additional quick bars. But if you can play in 1920x1080, they arn't so big anyways. But i suppose it depends on if we get more skills to use than before.

From the videos, the alpha GUI looks pretty nice. Familiar and easy to use for anyone who is accustomed to modern, western mmos. I believe Yoshi-P had said.. maybe in the live letter.. that they wanted people who had played other mmorpgs to be able to sit down and play without much effort.

I remember reading someplace that in beta the UI elements would be resizable

I also remember reading that we could change the order of our party members on our screen. I hope this is implemented, it would really help out us WHM's. :)