I've been playing exclusively multiplayer with my wife. Here's my feedback for the developers:
1. Overall the UI is not that readable: I'm never sure who's turn is it, whether or not I made an action and/or move - I know that there are icons and the speed bar, but they should be more prevalent
2. The dialogues. Oh, the dialogues - countless times, when I wasn't close enough to get into conversation immediately I lost some of the lines. Also - I'm unable to change speaking characters between players (I can with my companion, provided that they are both in conversation). Using the space-bar to both skip the line and to select the first answer is also a problem. When in conversation between each other, I was unable to tell which one of us should click the line. And the most annoying thing is that I frequently miss which dialogue line my wife selected
3. With range attack, I frequently miss the fact that my character needs to get closer (sometimes they even leave the high ground) - we need a modifier key that changes the attack mode to "stand and shoot".
4. Would be a blast to be possible to assign any key to any action just by hovering and pressing key (with some modifier, to enable the binding mode)
5. I'd love to have the "cycle current character" key
6. And the "cycle enemies in sight" key as well
7. The marker for other player (when they are out of sight) should be visible not only on mini-map, but on in the game as well
8. The alt key doesn't show all interactive elements, it should
9. The alt key should not change the container action to pick-up, from the default one (open)
10. Ground that is a valid target for jumping should be highlighted, so I don't have to search the landing place pixel-by-pixel
11. In the inventory screen sometimes I see all characters, sometimes only mine - why?
12. Would be great to be able to click some location on map and have the camera move there, or at the very least click and order the character to go there
13. There should be a toggle for camera to always track the character
14. Right-clicking the the avatar on bottom left should open the Character Window
15. Right-clicking the avatar in the initiative list, should inspect the character (and if it's yours - open character tab)
16. Flying companions should automatically climb
17. When guest player wants to skip the dialogue line, the host should see that it's OK for them to skip
18. XCOM-like button to toggle aiming towards ground or towards roof
19. Shift+click on item in chest or ground should add it to wares
20. Shift-clicking on avatar should degroup the character
21. There should be a "jump with all characters" feature
22. There should be a way to permanently select the "Allow LAN" option in the session menu
23. The "empty" keyword should appear not only via alt key modifier, but on the top overlay as well (when you hover over the container)
24. Right-click over the name of alt-key highlighted item should work the same as right-clicking on item itself
We just finished the Early Access and oh, golly - we cannot wait for the full thing

Great work, Larian!