Couldn't agree more. The single hotbar in BG3 is a horrible mess. You shouldn't have to search for your abilities and items every time you want to do something.
Spells need their own interface. With level sorting and easy upcasting or metamagic.
Abilities need their own UI, where you can also tell by glance which short rest and long rest abilities you have available. Abilities granted by items should be bundled up with class abilities.
Consumable items like arrows, bombs and potions need their own sorting.
And finally, temporary actions like reactivating Witch Bolt or hurling Produce Flame need to appear above basic actions like Attack and Disengage.
Effective sorting should work better even on a controller. The UI rework should be a priority since it's so fundamental in how the game plays.
