The smart AI goes both ways. If Bohemian policymakers rightly decided you are a threat, there's a simple solution.. you rival them, you look at who else Bohemia doesn't like (and vice versa), and more often than not you will find a big unexpected potential ally to help stomp your new enemy, or at least discourage them for attacking you! For example if you're little Serbia or Byz and afraid of Ottos, try to ally Hungary. If you're Kongo and threatened by Portugal, write to the Dutch.
I really hope that Paradox does not "nerf" the AI at all in response to these complaints. Just give the complainers a new lower difficulty setting with carebear non-aggressive AI. I would like to see even tougher AI available, maybe not the international badboy wars of olde, but something to discourage formation of giant player empires in MP and make it more balanced. Actually the AI right now is pretty awesome, the main problem is that it still fails at amphibious warfare, often it will try to land its army in little 4-stacks to be gobbled up by a defender, and it still does suicide attacks when it could wait for backup to arrive.