I read the Dune books after seeing Part 1, and I was slightly disappointed at how _little_ characterisation most characters have. Most of them have no history or relationships outside of the ones present in the book and very broad "Paul's doctor came from the secret society of very good doctors".
IMO Dune a good piece of literature, but the lackluster worldbuilding makes the Universe feel small and empty. Nothing interesting happened in the prior 10k years to anybody who's not a protagonist.
Fully agreed on this. The books give you no sensation of a galactic empire of trillions of people and all the complexity that would arise from it. The society has no more depth than a small European nation - a few corporations, a few universities, some guilds, an aristocracy, etc.