I agree with the fact that AIs should focus on capturing their state religion holy city if the owner doesn't follow that religion ... who said Crusades ?
To make things funnier, Christianity and Islam should arrive much earlier in game so they could have a chance at playing an important role in the game (maybe they should only require Monotheism + Writing or Monotheism + Writing + Monarchy).
I would quite like to be able to choose which city gets to found the religion. But then I suppose if a player founds more than one religion he will just put them all in one city to leverage the wall street multipier... potentially you could then have ALL seven religions founded in ONE city which would be odd to say the least. so probably not a good idea.
At first I also thought itwould be great to be able to choose which city would become your holy city and like you, I found out that it could be spoiling the game with people picking 1 super holy city.
But I think that the selection of the holy city should be A LOT smarter nevertheless. I mean ... I play as Romans, I capture Vladivostok and during the next turn I complete Divine Right research and Islam is founded in Vladivostok ???? How logical is that ? 5 turns later Russians capture Vladivostok
Imo, the game should take several facts in account for selecting which city becomes a Holy City :
1. A religion can only be founded in a city that has 100% of your cultural influence -
so no freshly captured city and no city that is close to flip
2. A religion can only be founded in one of your 5 most cultured cities
2. A religion can only be founded in a city with a pop cap > 1 -
would only kick in if you have more than 2 cities with a pop cap > 1
4. A city can be holy city to 3 religions maximum -
would only kick in if you have more than 1 city of course
5. A city which had a "holy" random event (holy water in oasis, holy walls) will most likely become the holy city of the next religion you'll found.