Your idea of "tell the AI what to say 'meh' to" is bang on.
The Basic Number One Question About AI In Gaming is: The AI's never going to be as crafty, as able to think ahead or as able to learn from past mistakes as well as a human would. So how can AI be done so that it's inherent weaknesses are hidden as well as possible?
Let's face it, 90%+ of complaints about AI are along the lines of "Why did the AI do this screamingly dumb thing?", which says to me that the AI screws up in ways that to us humans are obvious and it always does that if the AI's put - or allows itself to be put - in a certain situation. Not to say that humans don't screw up, logicially every multi-player game is lost because a human does something stupid, but it's not a If Player A Does 1 Player B Always Does 2 And Loses Every Time thing.
I guess the best we can get is "random stupidity", which is actually pretty damn realistic. Humans can be very stupid, randomly. You make a basic mistake in Game 1. You resolve never to make that mistake ever again. You make the same mistake, having forgotten your lesson, in Game 45...