Also, look at Two Face's "replacement!" False Face had his ENTIRE face covered up in such a way that NO one could tell what he really looked like!
A little bit of make-up, and Two Face would be SET. They could make him into a semi-tragic figure like Mr. Freeze, whom Batman wanted to help escape his ice suit, or King Tut, who was always ashamed he'd gone back to his evil ways after a bump on his noggin.
Two Face could VERY easily have fit in on the 1966 TV show.