Sammartino and Backlund-Hulk Hogan and Randy Savage-Bret Hart, Undertaker, Shawn Michaels-Rock, Austin, Triple H-Angle, Jericho, Orton, Batsita, Cena,- (future) Punk, Sheamus, Bryan, ???
Thats a fairly decent flow chart of how the WWE has dealt with wrestler leaving throughout the years...