I think it would be cool if the classic (retro) skins were able to perform one classic Ultimate (No Mercy) Combo.
Jago: Crushes opponent with a vehicle
Orchid: Frog crush (boob flash probably will never return)
Sadira: Wrapping in web and hung upside-down (just made that one up but would be cool to have an exclusive finisher for her alt. skin)
You get the idea!