Thanks for all the feedback.
Well, the Codices aren't really meant to be balanced. There are obviously ones that are better than others, but overall their uses and properties differ enough that people might enjoy one more than the other. It's not like Pages of the same Codex have the same powers, either. Can't talk any more about that, since I do want to keep some mystery in there.
Ah, yes. TvTropes. I'm hoping this thing will end up on there someday.