That's a great feedback. PoE2 had a neat system where you select a spell level and then you select from the known list of spells. Considering the variety of spells and items and other things that we can place on the hotbar, the management is a mess and I'm running out of space very early on.
Why not steal from a good system? Select a slot for cast, then the appropriate spells will show up alongside with "upgraded" spells (i.e. Magic Missiles in 2nd level slot). Cantrips can be it's own menu and then we're left with some form of scroll and backpack menu. Yes it would require 2 clicks but organisation is much more important imo.
I think this would be great. They could even add a customizable favorites button that you can mark spells from your book to be condensed into the button.
