How about releasing a "mega tome" that contains all the rest of the cards needed to get 4-6 of each spell when combined with the base set?  This should not replace the "core spell tome" but would be an alternate choice for those who want the "complete" set.

I know there were "tough choices" involved, but my personal preference would have been to have the core set come with 4 pre-made wizard starter decks (each in a little box or plastic) and a few less extra cards.  I realize it is a two player game, but I want to try out all the wizards without having to shuffle cards around.