I did a search to see if there was a topic discussing the current state of the game UI and suggesting changes or things that are made harder because the UI isn't designed to work better. So here are some of my thoughts. Generally, I dislike the UI in it's current state. Both the game hotbars and information windows are not as useful as they should/could be and the Equipment/Inventory windows are frustrating for me to use.

I really dislike the rotating hotbars in their current state. First you can't expand them enough, they can quickly fill up and the controls to move them to the next bar up or down are difficult to select. Hotbars are used in most games, but I would rather see the bottom bar used for items and actions and a flyout like what WOTR uses for spells. I'm generally okay with the flyout Information window and the character portraits work fine. Still I would very much like to see something much more useful designed. This has the look of a placeholder system and I hope that is the case, but if not, I'd rather Larian know that this is not ideal.

The equipment window mostly works. I like how when you go to equip something like a weapon it pulls items from anyone's inventory, but when you want to swap items, it would be even better if those items would appear as well so I don't have unequip it from one character in order to equip it on another.

The inventory window in my opinion the most irritating of the UI. First, you can't re-sort by the same sort without having to change to another sort and change back. Second, you can't multi select items to move items from one character to another or to the camp chest. Also, I would like a option to view everything other than the Miscellaneous (inventory candy) items. Honestly, I would be perfectly happy if those items are just hidden unless you selected the Misc button. Additionally, it would be nice to have a Trading option that would just automatically move all Miscellaneous items to the trader. By default, any item that does not have a game significance should be designated 'wares'. JMO.

Trading window. Really would like the option to hide the items that I have sold them from the ALL button. I have no intention of buying back inventory candy, there is really no reason IMO to show that stuff to me.

Highlighting items. Sometimes I discover hidden items using perception, I may be remembering this wrong, but can these items be highlighted in any way? Often, I really don't know exactly what I found. Tab might do it, but again, it just doesn't always stand out, maybe use a different color to highlight the item?

This is all I can think of ATM. I would love to see some discussion about how better to implement a better UI experience.