They should just look at Solasta, again.
You click a spell, that opens a small popup upon this icons with 1/2/3/4/5 and the player just click the level of its choice. Easy, clean, better.
Or at least the actual "popup" should adapt to the number of levels you can choose.
It's absolutely terrible to open a 18 slots window if most of them are empty.
2 levels available for a specific spell = 2 slots "popup".
3 levels = 3 slots
...
That's another clean possibility but I'm not sure it's possible to have something easy to read and understand with the awfull MMORPG hotbar.
Maybe if the available level slots opens verticaly upon the hotbar icon.
The problem with your suggestion OP is that every spells don't have more levels and some spells are only available at a defined level.
If spells are sorted in level tabs it's gonna be very hard to find what we want and we'll have to click more than once to find THE spell.
Last edited by Maximuuus; 05/12/20 04:57 AM.