CHA limiting spirit magic makes sense. CHA also limits how many spirits you can have bound. INT used to be an important stat for modifiers, and getting skill increases once skills got over 100% (or maybe this was just a house rule we used). Now, unless we are talking sorcery, it seems like dump. Seems like the only reason to have it is to put another limit on sorcery. And, yes sorcery is a the realm of the Logic, so INT should be the prime guide. That is fine, but the mechanics are not that great so far.