Don't get me wrong.. the UI is not broken. Although some people will argue that it is using hyperbole like:
The UI makes me want to tear my eyes out with wolverines claws...

Those people over exaggerate. The UI is fine... is it the best UI ever? no.... but its useable and functional.
It is sluggish.. but I don't know if thats the design of the UI or the server structure.
the "Please Fix it" threads are a little over the top because they imply that the system is broken.
If it was "Broken" it wouldn't be useable at all.

Since the UI is being redone from the ground up, I'd like to see multiple options that would accommodate everyone.
So the current UI would be one option. Or an up to date 3D version of the old "Secret of Mana" UI could be another
Who knows?
Think of all the RPG's you played on console? which ones did you love? which ones were annoying?
Which ones have elements that could be used in an MMO?
And lastly its about a personal preference.
Nested menus? hot keys? combination shortcuts (i.e. R1+Square on a PS style controller)? radials?
I don't know the perfect UI... If I did, I'd be a game developer.
SE is tasked with giving us a UI that doesn't hinder us, that becomes almost transparent and lets us explore Eorzea without fail
Im interested to see what comes up