We all know his knees are pretty much rotted out, he's been a face his entire WWE run. My thought is, what if he had his final run as a heel? Have him come back and only wrestle in boring, slow, submission filled matches. Have him constantly tease high flying spots only to swerve the crowd and build his heat. It's also a good way for him to go easy on his knees and avoid other injuries. This way when they bring up Del Sol who has the chops to be a proper "replacement" it makes for a much better feud. Rey jobs to Del Sol at Mania where he finally busts out some of his classic moves, shakes his hand, passes the torch, and retires the next night on RAW where he'll be cheered once again.