I feel what was done with spells was a very good thing - in the click, and choose the level.
I would actually suggest hiding all the spells into ONE menu- a spell book on the hot bar- making it similar to the how it works for choosing the level of the spell.
Click the spell book, and it has tabs, 0 through 9.
Click the 1, it shows all the level 1 spells, and only the level 1 spells that are memorized and usable.
Click the 2, shows all the level 2 spells, or spells that take level 2 slots.
etc etc.
Choose the one you want, click, target, click, move on.
I enjoy having everything at a glance via the hotbar style. Having to flip through pages would be terribly disruptive and would break the flow in the general overview of information for me.
I'm not saying what's in the game right now is great, but I prefer it far more to fiddling with tabs and then having to recall specifics between those tabs.
