Let AI Destroy buildings for three reasons.
- Muslim city gets conquered by catholic. Then by Pagan. I conquered this city and I see 5 religious buildings. The pagans effectivly played with 4 building spots there!
- lategame provinces have 8 buildings. The AI that conquers this region needs a resource that this region can provide. They just do not destroy any less priority building in that situation
- AI builds 8 horse farm buildings in 12 provinces owned or conquered. Just let them check for these buildings, destroy them if more than 2 of them exist.
Change the building priority if needed so they focus building their own advantages.