Shouldn't Dark Kahn be a seperate character from Shao Kahn, even if it's influence comes from DC (like Raiden and Shinnok, who both went dark differently) or should he remain as some sort of a fusion? His moves would be different.
He'd be his own character, despite his origins, just like in the actual MKvsDC game. If it were just a costume update (like Dark Raiden and Zombie Kang) I would imagine it's the same dude.
Devil Jin... Devil Kazuya... all "different" characters too.