In combat, I often use the same spells over and over (whatever the single direct damage or group direct damage spells best for my setup are, and maybe a buff or two that I use often).  It's frankly a pain to have to open the spellbook repeatedly to just cast this small array of spells.

My suggestion is to provide a quickbar just above the dashboard when a spellcasting sov/champion is active.  Each button would have the spell icons only from the spellbook, shrank down to a size that makes them legible, but not in the way of the rest of the tactical map. 

I can think of two good ways to populate the five buttons:

-Let the player drag spells from the spellbook down to the quickbar when it is open.  So my Sov's turn comes up and the bar is empty, or i want to replace a spell in it.  I open the spellbook, drag and drop the spell I want into slot 1, and close the spellbook.  Slot 1 stays with my spell of choice until I drag another spell over it an replace it.

-Just populate the 5 slots with the most used spells, in descending order of use.  I use fireball all the time?  It takes slot 1 and inferno takes slot 2. 

I could see the additional benefit of having the numeric values of the slots correspond to hotkeys to quickly select casting the spell as an action.