the AI is not a valid argument. generally speaking, let's say there's a performance difference of 10 times between ps3 and wii, that doesn't not translate into "10 times better AI that you can perceive". good AI requires clever programming and not brute force. it's prohibitively likely you can't at all tell difference in AI given the same code for the ps3 and the wii.
now, i'm not in the gaming industry, but i'll say better AI really does mean hiring programmers who actually know AI well. i know a lot of programmers and most of them have little knowledge of AI. i know one specialized AI programmer but i gather that they get paid a bit more and don't work for gaming companies.
i don't think we're at the age of good AI yet--it's "current research" and doesn't seem to be ready for prime time. give or take another 20 years.the Wii is an epidemic.