The Dom3 AI isn't that great, but for the first couple of dozens of hours you won't notice it because you'll be too busy getting stomped by it while you are trying to figure out which strategies work
I think a lot of people forget that Dom3 has a pretty steep and long learning curve, so even though when you are at the top of it, you look down at the AI with contempt and can barely spot him ("He looks like an ant from here!"), you did climb a very long way to get there, and were looked down upon by the AI for quite some time.