I doubt that Ritual Casting is going to have such high ability score requisites. As far as I've read, Clerics and Wizards get Ritual Casting as a free feat, but if they didn't have the necessarily high ability score, they couldn't use it, which is anachronistic. Nah, if at all, it will be probably just 11+, and that's it.
Interestingly, that might even finally allow normal commoners to perform rituals, especially dark and evil rituals. Normal townsfolk who gather in the night and sacrifice goats, virgins and strangers are a classic.