I'm a big Lesnar mark. Go ahead and bash me for that, I don't care. I respect the things he has accomplished as an amateur athelete, and he was pretty awesome in WWE. Probably his only bad match was his last match with Goldterd at WMXX. So I'd love to see Lesnar return but that probably won't happen for the time being, or ever for that matter.
I'm going to agree with the majority here and say Rock and Austin, because of the entertainment value they would bring accross. Rock and Cena bashing each other on the mic would be classic. Austin is just Austin, and just that alone will bring up ratings.
Y2J would be nice to see again, maybe like a special apperance or one last match.