[HoneyBadger]

I don't understand AIs very well, atleast the kinds of AI that manage computer games, but I can vouch for what Arralen is saying about the use of arbitrary moves. What you don't want is the AI doing something stupid, atleast from the viewpoint of the AI (and for this purpose, you want an AI strong enough to see what the "average" person is going to see, atleast at a glance). So, if you create an AI that can eliminate the obviously stupid moves, and then narrow down the possible remaining moves to the point where whatever it does isn't going to be hideously disastrous, then a nice random choice isn't too bad. Then you start feeding it basic, general strategies that it can follow with it's simple, simple computer mind, and reference against what the player is doing, and then you leave it alone. It doesn't require a mainframe, because all you're asking from it is to put limited options into limited categories and then flip a coin. The computer doesn't bother looking at every move to the 10th place, it just looks at what's apparently bad and apparently better, and compares that to what you're doing, what the other players and AIs are doing, and makes a solid decision. People and animals operate in somewhat similar ways, which is why we call AI AI. Knowing that the world is too complex of a place to know every detail of what's going on, what's happened in the past, and what the consequences are for every action, sometimes you just have to do what you think is best, while trying to avoid hideous disasters.