I personally hated the auto clutter of disposable items on my hot bar and deactivated the option to have them auto populate. After that you can assign items by dragging them from your bag or spell book to the bar. Dragging from hotbar 1 to hotbar 2 seems more work than just opening hotbar 2 and dragging the arrow or spell or grenade you wanted on the hotbar.
Now the ability to expand the hotbar to show 3+ rows as well as multiple columns may be nice.
What I did find myself doing is having spell level 1's across the top row and then right below I would have level 2 spells of the same magic right below (started originally stretching across in sequence, level 1 level 2 spell of same type, but quickly became unorganized and not "OCD" pleasing.
If there is a potion or throwable I want to use I just open my bag and double click it there. Helps with the clutter in the hotbar. Not the answer you were looking for, but just a suggestion.
