I definitely anticipate a Part 3 after the success of the first two. Don't tell me that worm riding scene wasn't worth the price of admission alone! Like I said, the seats in the cinema were literally shaking during the scene. I couldn't even sit down afterwards because I had such an epic experience.
I was reading about a man in his 60s who was crying at that scene. Because, after first reading Dune nearly 60 years ago, at long last he could witness on the big screen the way he'd envisioned the scene in his mind for decades.
I think 3 will be based on Messiah but with a new message, that sometimes who we think are heroes are anti-heroes instead, as Herbert intended with this book.