A character who looks like Elijah Wood is far creepier to me than one who looks like Frank Zito. Because --you know what?--I know enough to stay away from someone who looks like Frank Zito. I won't ever be in a situation when I am close enough to Zito to have him stab me or kidnap me or whatever. No way. I'll just cross the street,
Someone who looks like Elijah Wood, however? Not threatening at all in appearance. And that's why guys like Dahmer are so "successful" at doing the horrible things they do. They are unassuming. It's terrifying when they reveal their true selves.
I don't see a problem with switching up the perception of the killer in the role. I don't want to watch the same maniac/"Maniac" again.