How? For one thing, the “Prelude to Dune” series is neither consistent with Legends of Dune or the Frank Herbert canon, and really adds nothing to the series.
For another, outside of the first four1 Frank Herbert books, the rest of the canon is awful.
1 As noted elsewhere, some other people mistakenly believe that this number should be three.
I’d think another problem for film makers would be Dune’s (the book) ending. SPOILER ALERT!!!: Dune ends with a hand-to-hand battle between Paul and Fayd Rautha. That sort of thing does not amount to a Hollywood blockbuster ending, which explains Lynch’s movie ending (the idiotic conjuring up of rain by Paul).
I agree that it’s a book about ideas. But then Denis Villeneuve did Arrival, which is a movie about ideas and their effect on society where a lot of the action happens in the main character’s mind. I would argue that if anyone is going to direct Dune, Villeneuve is our guy.
Paul claiming his place with the Fremen through the Stoneburner/wandering off into the desert is a LOT of ground to cover in one movie.
I would think it more likely to mimic the Siffy “Children” miniseries and combine Messiah and Children… The problem there being the loss of almost all the main characters between movies 2 and 3.
Consider that the movies can be a good 3 hours long and not be excessive for the genre.
(LOTR is 9 theatrical hours total, 12 on the extended Blu Ray. 4 hour cuts!)
But I agree that basically the best thing would be to flesh out the original Dune book into three equally-balanced episodes, then Messiah/Children could be three in its own right if they’re still cooking, perhaps with God Emperor as the last of them.
For my money, the internal dialogue of the characters just isn’t necessary for any adaptation. It didn’t work in the Lynch version, and one didn’t miss it at all in the miniseries version. Basically the inner dialogue is just “character subtext” – something to be conveyed in performance.
As much as I like Children, I think God Emperor would work better as a frame story where Leto reveals the Golden Path (as long form flashbacks to Children) to Siona. Xanatos Gambit style.
It would change the book canon but no movie would be able to avoid changing canon somewhat anyway.