I think in recent titles, the AI have become good enough to not use glaring cheats like in CK1. But there might be places where they have to let the Ai do "cheaty stuff" to make it work as intended. I am fine with that.
What I do not want to see from the AI:
- Less attrition than the player. It should be smart enough not to load 50k troops into a desert province.
- Free finances. Be capable of handling costly wars AND finances without the CK1 no-debts-cheat.
- Greedy lieges. The AI not claiming every title of vassals that border it's personal provinces. Makes it really hard to play as a loyal subject when you know your king will be gunning for your lands eventually.
- Excomming villy-nilly. None of this nonsense of excommunicating anyone and anything it can within reach, just for the hell of it. Excommunication should be only used by the PC sparringly, and for the AI reserved for true rivals.
- No Defence of the homeland. Be capable of defending it's homeland when at war somewhere else. I doubt that the King of England would move ALL his troops to France for a war, just to see the welsh, irish and scots rise up and take over the british isles with no or little resistance.
- BB free. AI should get BB just like the player, so if HRE hyper-expands, then other rulers might gang up on him. The Ai should recognize BB as an issue and be able to handle this by giving out titles, even if Intrieque score allows for 100% efficiency. Also Ai should be more willing to give up a far-flung personal demesne of high income, instead of giving away a lower income province in the homeland. This should keep the ruler's power centralised and not make HRE have two provinces in Germany, one in Sicily, two in the Outremer, one in Iberia and one in eastern Russia.
-Suicidal tendencies. On any aggression level above 'Coward' the CK1 AI would go to war with ANYONE it had claims on, even with absolutely no chance of winning. This helped the blobbing on the map. The AI needs to be better at biding its time for when the time comes to strike, instead of just striking when it can.
- Same laws across the map. The AI should be able to handle changes of inheritance laws, realms laws and religious laws (assuming that all those will still be there in CK2). This only happens by event in CK1, but would be nice if the AI was capable of seeing the benefit in changing their laws to something else, depending on the situation.
Those are the changes I could think of right now ... but basically most of the AI would need to be changed in CK2, since CK1 AI was pretty moronic and incapable of even the simplest of decisions.