With the most recent patch, the AI has become far, far more aggressive, to the point of near insanity. It will declare war for seemingly no reason than someone else being near them. Further, wars between AI nations do not ever seem to end. This is beyond absurd. I'm just making ramblings here, but I honestly think these suggestions may have some merit.

First- In order to make the AI calculate better the cost and reward of declarations of war, I propose that there be a prestige penalty to any nation that declares a war of aggression- that is, so that the penalty would only apply to instigators of war, not to allies that join on either side of the conflict. Obviously, this would mean having to program a way for the AI to value prestige highly. And particularly for prestige campaigns, this makes quite a bit of sense. Europe definitely had its share of wars in the 18th century- however, wars were not declared on a whim- they had an expressed purpose as a tool of furthering national prestige, and I would really like to see CA emulate this better.

As for the AI actually stopping wars against other AI nations, it seems that the system is completely broken right now- until the AI actually ever offers peace deals, there isn't a whole lot that can be considered.