Yeah the AI is pretty retarded when it comes to planet colonization . They also ignore anomalies for a long time which is weird
Now, to be fair, the AI(s, there are several) is an EXTERMELY complex program, and it is making a large number of decisions. We can't see all of those decisions, and so "retarded" behavior isn't always a sign of inadequacy. That said, the program IS very complex. Anyone familiar with complexity will tell you that complex systems can develop quirky behavior under the most optimal circumstances.
Add to this that the AI has to be updated to deal with new variables every time new variables are added to the game. Ideally, an AI would be designed to consider variables in a modular way, such that changes to the parameters of the game wouldn't really affect it. It obviously does do this, witness the way it can use the ship designer, despite changes in the costs and sizes of various components. However, Dark Avatar significantly increased the dimensionality (if you will) of the space in which the AI has to deal with colonization. It now has to assess not only the current and future potential of a world and its environs, but also its own progress vis-a-vis colonization technologies, and presumeably an overall strategy for dealing with exotic worlds.
So, it may appear retarded, but that is just the result of sophisticated coding!