Right now we've only seen a portion of what the new UI has to offer. So far, we've seen the action bars, character status bars (health, mp and tp), the party formation, the mini-map, the micro menu and the character creation screen. What we haven't seen yet are the actual menu's, like: Inventory, Equipment, Point Allocation, Actions & Traits, Linkshell Management, the contents of the mail box, the configuration menu, etc.

There is still so much we haven't seen yet. As far as we know, SE might even have more then 1 UI preset we haven't seen yet. (For instance, one that resembles the current UI appearence, but with the flexibility of the new UI).

On top of that (like others who've already mentioned this in this thread), the 2.0 UI would be customizable with add-on support. If you as a player don't like what the UI has to offer, you are free to change it to your liking. If you are a seasoned "modder", you might even develop an add-on which enhances certain features the game/UI has to offer.

Personally, i like the new look. It's new and fresh. Something i haven't seen in an MMO so far. I'd probably stick with this UI.