My only issues with the apprentice spell book is that the warlock has no way to remove curses. I also feel the Gorgan Archer is OP for the apprentice book.
I have had several apprentice matches where the Gorgan Archer completely neutered the Warlock with Weak Counters. last night i was playing a guy, I was the wizard and the warlock ended up with 5 weak counters.
I haven't played loads with the apprentices, but I'd think you should be able to avoid this. The obvious thing would be to just get in the same space as the Archer and smash it! Even against regeneration, damage plus burn effects should be effective. If you've summoned something else, that can help, or go for the other mage.
I've heard about other problems with other books, though: the main solution is just to move on from apprentice books. I think they're intended to introduce the rules, not as a constant 'lighter' version of the game.