Your idea reminds me of something I've wanted--religious schism. You could also add great philosophers for governments and civics. And even (gasp) government types based on Eastern Cultures. We could have a Legalist Government. Or a Confucian Government. (Alternatively, they can be worked into the existing governments in a better way) I'm trying to think if there were features in Rhyes and Fall that have never been implemented and I can't think of anything.