What about adding in a minor penalty for Grigori cities with a religion in them? Something like a +5% to maintenance for each religion. This would give them a reason to remove the religions. As it is now religion only benefits them. Of course this would only be fair if the Luonnator got back their inquisitor function.
Related note: The cultural flip and religion spread can be illogical at times. Imagine a Grigori city bordering on an empire running OO as state religion. OO spreads to the Grigori city granting it +2 culture per turn. This makes it harder for the OO empire to culturally take over the Grigori city when it should actually encourage the city to jump to the empire. A very minor issue probably not worth addressing but thought i'd point it out.
Related note: The cultural flip and religion spread can be illogical at times. Imagine a Grigori city bordering on an empire running OO as state religion. OO spreads to the Grigori city granting it +2 culture per turn. This makes it harder for the OO empire to culturally take over the Grigori city when it should actually encourage the city to jump to the empire. A very minor issue probably not worth addressing but thought i'd point it out.