I honestly don't care what Yahtzee reviews, so long as he plays -something- and says what he thinks of it. If he keeps getting asked (read: made) to review horrible games, just so we can laugh at his disgust, he's going to start hating games entirely and grow (somehow) more bitter and disgusted with the medium like any sensible person. Yahtzee's appeal to me is that he takes even good games like The Orange Box's contents and points out where they fell short; that kind of criticism is more useful than just talking about the good bits. Game developers will keep making horrible gameplay elements (see: "God-of-War-Simon-Says-etc.") unless reviewers and fans tell them they don't want to play games with that kind of stuff.
So in short, he should just be allowed to play whatever he wants, so long as he puts out another review-film full of wit and humor. I'd honestly like to see some retrospective reviews/editorials like he did with "Fable;" even a written retro-review of System Shock 2 would be neat, just to hear his thoughts on a game he liked (unless I interpreted his Bioshock review incorrectly).