I tried to read the DUNE books back in the 80's and simply could not get into them at all.
I did watch the movie when it came out; I recognized its technical skill but the story just left me cold.
I'm completely with you, I have only read one dune novel and it was a later one and it stunk to high heaven. If it helps you to get it, dune was a novel about the importance of ecology. This was written in the 60's when ecological awareness was in it's early days.
It was also about how foreign powers can invade and disrupt a society shaped by a certain ecology. This was a direct reff to western culture invading the emideast for a vital resource, oil. Arakkis was a model of the mid east and the spice represented oil.
It also represented power plays and intrigues between major powers.
Dune wasn't my thing I respected it as an awesome SF epic that just wasn't to my tastes.
As to he movie I agree, magnificent cinematography and epic scale and ambition, but too sprawling and plodding. I think the director was determined -BY GHAWD! - to make an epic movie, not just the best movie he could, but an epic movie.
Also, in the end, the dune novel was likely just too deep and demanding to make a movie of that would be successful. Some books just a can't be made into a movie.
If you want to read an excellent SF novel that's deep, try "solar express" by Modessitt. He had the guts to make the Chinese the villains in it.
