Making the Harkonnens bald was actually a bad idea
You see, it worked in the first film because it removes a very important hint about a certain central character's secret lineage by hiding the fact that the Harkonnens are famous for being redheads. (Although recent readings of the book reveal that Feyd Ruatha was a brunette).
But it destroys something that defined Feyd Ruatha. In the books and in the two previous versions of "Dune," he was supposed to be a very handsome (if evil and sadistic) young man. You take away the hair and it ruins any attractiveness the character might have had, and frankly, this version of Feyd just looks like a younger, skinnier, shorter freak than his brother and uncle.