I'm not against Rock doing the odd personal appearance, but the only context in which I can see it happening now would be in a skit with Carlito, which would be a waste.
We'll see if one of the new smackdown guys can fill the Brock role, if not I'd be happy to see him return.
I thought Mike Awesome deserved another shot after his One Night Stand performance, even if he was working with a guy who knows how to carry him he won the crowd over tremendously.
Interested to see if Rhino can mount a comeback, though if he can shake off Jarrett (ahem) he's better off where he is.
Other than that I'm not one for nostalgia appearances with the wealth of young talent available to WWE, and Corino has never impressed me as a serious character or worker.