Actually I've only played 1 game in the demo against the AI [the rest was MP], but the AI did very good. I've never seen such a huge AI army in a strategical position in Doms 2. Like I've said earlier, it moved ~700 troops to my border province, and it was the only land province in that area. I was fighting on south, so it was a ehm... a big surprise. That army easily took 2 of my provinces in the north.
The game just ended after that.