The biggest problem is the problem that plagues seemingly all prequels: the fact that no matter how far back in the past the story might go, imaginations can only stretch so far. Once again there is a conflict between the Harkonnen and the Atreides families (the novelty here being the Harkonnens get more screentime),

A long-gestating prequel, about the women who seek to guide a galaxy, is splashy, somber and insufficiently spicy.