A dark, twisted Bowser would be awesome.
Ganondorf or a Ganondorf armor set for Shao Kahn would be cool.
Ridley is already pretty menacing and would fit in well.
I could see one of those characters possibly making it as a Nintendo Switch exclusive. Someone like Link, though really a fun prospect, might not have as great as a chance. We’ll see soon enough!
(And in addition to this, I’d be stoked to see Scorpion, Sub Zero, or Raiden make it into SSBU.)
Hey, if SNK can turn Terry Bogard into a girl strictly for the all-female SNK Heroines fighter, then I don't see why the hell they can't give us a "mature" Bowser or Ganondorf for the Switch version of MK11.
Nintendo probably won't allow it, though, sadly.
Though if they are gonna go with the console-exclusive characters route, then the PS4 version should have Kratos or Sweet Tooth. Sweet Tooth in particular would blend in quite well with MK.