1) Improved demarcation of class abilities - eg. scrolls only being usable by classes the spell list appears on, including Wizards only learning spells from their list; make disengage and hide an Action so that Rogue's Cunning Action feature feels significant
2) Separate jump from disengage - jump is part of movement, disengage is an action before movement.
3) Character creation UI - currently not enough information / tooltips, including clear information about archetypes/subclasses available at later levels so people know what specialisation to aim for as this impacts ability scores too.
4) Hotbar UI - currently too many different things combined. Personally I suggest separate "quick actions" hotbar for whatever you most commonly use, whether that's your weapon attack or a cantrip; and an "all actions" toolbar below it that has various pop-up menus for different categories like class abilities, spells, potions, grenades/arrows etc.
5) Declutter the world - reduce the number of placeables that allow interaction (whether looting or being moved around); and improve the usefulness of the "highlight objects" keybind (L-alt by default) so that it highlights ALL lootables and important interactions.
6) Reduce surfaces focus in combat. While some aspects of this should remain as it can make encounters more interesting, having too much of it feels too much like Divinity.