Herbert said his whole point in writing Dune was to criticize the tendency of people to rely on Messianic figures for salvation, to show how our reliance on cha

Herbert said his whole point in writing Dune was to criticize the tendency of people to rely on Messianic figures for salvation, to show how our reliance on charismatic heroes and saviors can destroy us. Ironically, there's so much propaganda in favor of these things in fiction that most people read his criticisms as support. He also wanted to explore the idea that reading about characters who operate with advanced levels of consciousness might inspire readers to expand their own thinking, especially into thinking about long-term consequences on our environment, to get people to think about living more sustainably as neo-peasants, which he attempted to do himself. So the characters are meant to be inspiring, but their flaws ar meant to be obvious enough that we can avoid the mistakes they make while thinking more broadly and surpassing them.