I'm not sure I'm all that won over the aesthetics of the Harkonnens. They look like a bunch of angry babies who've just stumbled out of a cybergoth nightclub. In the book there's a good deal of panache and decadence to them, so there's ample mileage in having them (or the Baron and his nephews, at least) look something like aristocrats from Imperial Rome or 18th century Europe, or whatever. Renaissance Italy. Feudal Japan. Ottomans.
Not that a film has to follow the book it's based on that closely, but it would have made it look a bit more interesting.