I have been playing a VH/VH Venice campaign with unofficial 1.2 and have been giving the AI factions significant amounts of money via console every once in a while.
I have noticed significant improvements in the campaign map AI and diplomacy. Enemies attack with large stacks at multiple targets at once. The AI always combines stacks to get large and powerful armies whenever possible, resulting in major battles at regular frequencies. The tactical AI seems to be slightly improve, but it still has problems. Even so, the vastly improved campaign AI makes tactical battles harder simply because larger armies are bring brought to bear against me far more frequently. I have yet to see any AI stacks hang around doing nothing. When the AI builds armies, it uses them, including coordinating competent seaborne invasions of islands. Iraklion and Rhodes have been under constant siege for me since my war with Byzantium started, even while they keep attacking Durazzo and Ragusa by land.
The diplomatic side makes far more sense as well. Even on VH difficulty, alliances hold very well and are easy to maintain. When you sign an alliance, you get a significant boost to your relationship with that faction, and I have noticed that the longer the alliance lasts, the more your relationship with them improves. If you attack an enemy faction, not only do you lose relationship with that faction, but you will also lose relationship with that faction's allies. That's a smart improvement and helps increase the emergence of long-term alliance blocs.
I also just experienced one of the most extraordinary events I have seen in either RTW or M2TW. From the beginning of the game, I have been allied to the Papal States. During that time, the Pope had maintained a full stack right next to Rome, but had never left his province for any reason. Recently, Milan attacked me and besieged Florence with a large stack. I had only 4 militia and a general in it and could not have won the battle. However, immediately after the city was besieged, the Pope moved his entire full stack next to Florence, which was attacked by Milan the following turn. I held off the Milanese in the town square long enough for the Papal army to enter the city and defeat the Milanese. After the battle was done and Florence saved, the Papal army returned to Rome and went back to its usual business.
It cannot be a coincidence that the first time a Papal States army left its borders in 50 turns was to stand next to an ally's town right before it was about to be attacked. That's a major AI improvement I had not expected to see.
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