Exactly, it would come back to looks, as i said in the post, it has nothing to do with anything, the way killers look is irrelevant, they are simply made to look disturbing to unsettle you.
So the answer to the question is answered in the original post anyway, ofcourse they would be different, they would look different, but they themselves wouldn't be.
Plus i was being extremely unwitty and sarcastic, i'm not talking about superman himself, it was just an example, the question is pointless.
Would Gandalf (from lotr) be different without a beard?
Would I be different if i didn't wear pants?
Would Joe be different if his cofee was switched with piss?
They all come back to image or just something that wouldn't affect anything; if they didn't have their knives, they'd still kill, if they didn't have the mask, they'd still kill, the image is simply there for entertainment/shock value, it plays no direct part to the story or the character in general.