Guitar Hero and Rock Band are a bad idea, Beat It (more of a rock song than the rest of MJ's R&B/pop repertoire) in World Tour is okay but that's only because Eddie Van Halen plays a solo on the song so altogether it makes Beat It one of the few GH/RB adequate songs from MJ.
Singstar and Dance Dance Revolution would be great hits with Jackson's music and I'm sure they'll make an appearance sooner or later unless the franchises die.