Finally got to see Dune Part One. Could have been more faithful with certain details, but I'm not too bothered by the creative changes. The important things-- general story, character portrayals, tone, visual style, sound/music etc. --were all pretty much perfect. Didn't feel as slow as I was preparing for either.
Unfortunate it still can't take off in the mainstream. I don't think it can be made much better at this point. Also wish it was 30mins longer so they could finish all the scenes pre-timeskip, then 3 years between filming would look perfectly natural.