I really appreciate the mindfulness of the decisions made to adapt the film to the screen, nearly 60 years after the book was published.

Chani being a non-believer made her relationship with Paul more compelling, especially when they made her part of the prophecy she rejects (although admittedly the way that was executed was a little corny). The reduced time spent at Sietch Tabr kept the pacing of the movie feeling consistent without the need for large time skip between films. And the rejection of Paul as emperor by the Landsraad makes the inevitability of Paul's Jihad that much more apparent.

None of these are changes that would have improved the book (except arguably about Chani's doubt in the prophecy), but they definitely fit the film without really detracting from its central theme