I am very picky when it comes to movies made from books - I can be picky, too, although there are lots of good movies that came from novels, e.g. Psycho, Rosemary's Baby, The Exorcist, The Godfather, Jaws, One Flew Over The Cookoo's Nest, Bladerunner, Let The Right One In, The Martian, etc.
Re Dune - I think the concepts are great. Even the Islamic influence is something I find interesting. I picked up a copy and saw in the glossary that Frank Herbert used real Arabic words, or Anglicisms which he invented. For instance, 'portygalls' means oranges, and this doubtless comes from the Arabic burtuqaal, which means the same.
It's a shame Lynch's film was so poor, because I like his other films.