Denis Villeneuve explains why he changed the characterization of a major player in Dune: Part Two
Villeneuve said he updated a character from the book to actually get closer to Frank Herbert's original vision

This story discusses plot elements of Dune: Part Two and the novel Dune: Messiah.
Even though Frank Herbert’s sci-fi epic Dune was originally published in 1965, a lot of the material feels chillingly relevant today. Like the multiple factions warring over the resource-heavy planet of Arrakis, we’re also razing our environment to the ground, constantly at war, and terrifyingly susceptible to the influence of enigmatic cults of personality. In Dune: Part Two, his sweeping follow-up to 2021's Dune, director Denis Villeneuve didn’t need to update much from the original text to conjure the images of violence and tragedy we’re all so used to seeing on the news. However, he did make one key change to bring the material closer to Herbert’s original vision.