This is a lot of work and you can tell they had fun with some of the animations and stuff, so again, thank you Larian for working on this.
Love the new button shortcuts for ungrouping/grouping. There's a learning curve, but a major improvement over what it was before.

Agree with everything that was said in this thread concerning the rest. My biggest complaint is:
1) No more ability to add buttons or to extend the action bar
2) No UI Scaling. The UI takes up too much screen real estate right now. Would be great to have a slider in the options menu that allows us to scale it to our desired size. The game is beautiful, I want to enjoy the scenery, unimpeded by the UI.
3) When opening the inventory, can it show the extended version by default ? i.e. when clicking "I", I want the inventory, not the character sheet. It's OK to have them grouped, and very convenient, but the extra click to extend when I specify that I want to pull up the inventory is a bit annoying. I do like that the sorting was fixed though. I would still like to see a quicksort button that sorts everything in one click rather than 2. Exactly the same as DOSII.

Some nitpicking items that have already been pointed out:
- The flee, turn based buttons are huge. I get there needs to be symmetry, but why not replace those with the actions that most new players will be using anyway -> Basic melee and ranged attack? Those buttons feel a little incongruous, like "WOW those are so big, probably something I'll be using all the time".