one issue that I've noticed in FFH2 is that most games end up dominated with just a couple religions ( usually FoL and RoK cuz they come early ) . this makes things a bit dull cuz of A. not enough religious conflict and most important B. if there are no AV civs around ( as is often the case if the sheaim are not in the game ) the end game gets really stagnant, which is quite obvious since with no AV spreading the AC ( which was designed primarily to address late-game stagnation and keep things fun as long as possible ) doesn't go up and civs are just shaking hands or barking at each other.
this is due to the AI still using vanilla mechanics for religion, but religion in FFH2 is TOTALLY different.
suggestion: make the AIs a LOT more willing to adopt religions they found. this will mean a lot more variety in practiced religions and make sure that things stay fun and don't drift into a RoK+FoL world