[Idea]: Spell books
Some people have complained that the factions and soverigns are to similiar and that there is not enough difference between them to make them fun. They have suggested several ways to make them play differently, and thus add to the "fun" factor of the game, and I agree with these critisms.
Something I have thought about is spells, though. All the books have very similiar spells and don't feel unique enough. Also, unless you make a custom ruler, you get all the spell books anyway; so again not very much diversity in play.
My thought was this, make more spells per book, and only allow rulers access to 1 or 2 books, that way soverigns really do feel unique because of what spells they have access too. Also similiar spells would no longer be a problem but rather a good thing in some situations.