Yea, I'd really like to see magic actually be useful in PvM, and not just at specific bosses designed to be fought only with magic, but at most of our current bosses too. Ancients is expensive but that's fine, it's designed for PvP, but I think a specifically designed PvM spellbook could make things really interesting.
I've had an idea for one in the back of mind for a while now, just never gotten round to putting it into words. The new continent I think is going to give us a new spellbook so there's a chance there