Here is my feedback on the Ultimate AI mod - it is utterly ridiculous and unrealistic.
At first it seems cool and diplomacy is meant to be tweaked with the aim of it being more reasonable. I was enjoying it at the beginning and even fought some massive wars against France as the Holy Roman Empire. Allies don't backstab you any more.
However, the further into gameplay you get, the more unbalanced it becomes. I owned every region in France, Germany and a half of Italy, not to mention part of Spain. I had towns with massive populations and many upgraded buildings, trade negotiations with the remaining factions too.
Every turn i'm in debt, I have 2-3 full armies protecting all those territories (lmfao) and the poorly though-out economy system does not allow me to build enough soldiers to even go on the offensive.
Major problems which are laughable:
- Unit upkeep is absurdly high, can't have more than 2-3 full armies for 25 territories.
- Impossible to gain favour with the Pope, not possible to join Crusades for the entire game (as soon as you attack a Christian nation and get excommunicated, you won't be able to get good favour with the Pope anymore, doesn't matter if he reconciles you). Bribing the papal states with money, completing missions assigned by the Pope, re-electing a Pope from your country, converting other religious areas with Cardinals DOES NOTHING to gain positive favour.)
- Ai spawns full stack armies out of nowhere lol (yes it does happen, I mean really?)
Conclusion: Don't download this mod. It may seem fun initially but further down the line you'll see how truly silly it is.