uncastable spell scripting (and can the AI cast newly researched spells?)

[lch]

I've always found it inconvenient not being able to cast spells that are in the spellbook the next turn, but can't be scripted in the current turn, too. There are some key spells that you need ASAP.

[Illuminated One]

I don't know, it would be nice theoretically but I dread the moment when I open the spellbook of a late game mage with 800 spells to select from.
If it was optional (press r to toggle between researched spells/all spells) it would be cool though.