I loved the movie, I'm still haunted by it days after seeing it.
As a huge fan of the book (I have read it 6 times), I was on board with pretty much all the changes made and I really do think they serve the story being told in a cinematic format.
There's one small change that didn't sit so well with me, though, although it might be considered quite minor. It concerns the nature of Paul's threat to the Emperor and the Great Houses, to destroy Spice production by nuking the spice fields. In novel, has many of you now, he threatened to destroy the whole Sandworm lifecycle, and therefore the spice itself, by pouring Water of Life into a Pre Spice Mass. This would obviously require quite a hefty dose of exposition and lore dump to explain the exact nature of this chain reaction and I can, for that reason, understand why it was simplified. But still, the book version felt much more like universe-shattering threat than nuking the spice fields (which I reckon would drastically, but temporally, disrupt spice production, but not destroy it definitely).
Just a small gripe. I would have also love to see some glimpses of the Spacing Guild in this, but Denis knows he will doing Dune Messiah in the future, so I'm sure he's saving some of that stuff for the next movie