There are several issues concerning the AI's actions on the strategic map, some may be bugs, some may be deliberate AI policy. While there are several, I'll just start off with one.

In my earlier campaigns my first impression of the strategic AI was that some factions were more aggressive than others. That may or may not be true, but I think now its all relative to economy, shared borders, and diplomatic status.
Can a AI faction be so aggressive that it just ends up going "stupid" on you? Or are these just game mechanics at work to keep the pressure and intensity on the human player?

An example I'll use here I know you have all seen. You have several frontier cities bordering an enemy faction. They are assaulted regularly and you defend them frequently. At first it appears the AI makes a real attempt to take the city, but you crush them because you had good defences, good units and a great Governor. Yet the AI persists and continues sending armies to this city in attempt to take it. 90% of the time though, it's a rabble group consisting of weak units that don't stand a chance in hell. Yet the AI keeps sending 300 leaderless troops against your 1300 man strong superfortress. If you can get one unit outside your gates, the AI is usually running. Turn after turn, it lays siege to this city with a pathetic group. Why not wait a few turns, get a leader and 1000 more men and make a "real" attempt?

I'm going to make a comparison with MTW and although it is a different game, I think it warrants using. The mechanics are the same for most part. In MTW the AI would make a real effort when it attempted to take a province. This is what made the battles great, when it tried to take something from you it really tried. I think it did a pretty good job assessing what you had and what it had and when to attack. When there was a battle, it was something to behold. I also believe it was a corner stone to its diplomacy unlike RTW. If you had good garrisons for your border provinces, it more often than not kept the alliance in check and vice versa if you didn't. With RTW we have more battles, but most of them seem redundant and pointless because of this "false" seige move the AI does. Loading and unloading of the battle engine just to see 200 peasants run for the redline for 1000th time is getting annoying. Get your cavalry out and run them down before those marathon runners make it to the beach is often tricky to pull off. And if you happen to be playing the Britons and have only chariots, don't even bother.

Oh, I didn't want to make this into a rant. Ok so, your thoughts?