I think
Dune is a great example of 80s excess. Although it obviously couldn't fit everything in, it sticks quite close to the novel, even to the extent of having the characters inner thoughts expressed in voice over (italics are used in the novel).
Far from being too long and boring I thought it was too short to do the book justice. I think at the time it was criticised for being too complicated, which is perhaps, more of a reflection of the dumbing down of films for 80s audiences and therefore not playing to their expectations of simple action/plots. It will be interesting what approach Villeneuve will take in this respect?
Anyway it was better than Star Wars: Return of the Jedi...