The Sci-Fi Dune miniseries was actually pretty good, I think, but you have to understand it as a filmed theatrical production rather than a "television show". I think this is in the abstract a decent choice since theater language is probably more appropriate to a Dune adaptation on the given budget than a "television show" adaptation, but it does mean you have to go into it with a substantially different mindset than you may have expected. And I don't expect everyone to like it even if they do go in that way because that may not be what they are looking for.
It's how they deal with not having the budget to actually put people in a desert so it's rather visibly a desert backdrop at some points, it's why the lighting is often so strong and monochromatic like a theater's lighting, it's why the acting is with all the characters projecting as if they are speaking to an audience rather than in a TV production. At one point they even use a very theatrical special effect based on backlighting through a thin cloth representing a tent to show Paul's hallucinations/thoughts, rather than even a simple bluescreen or conventional image compositing effect.
The effort is interesting, but I'd have to call it ultimately a failure (even if I personally ultimately enjoyed it) as it almost completely failed to speak to its audience. I also think you can't really follow it if you didn't read the books, which I consider a major flaw of an adaptation.
Really? It's a decent enough book--and I like Clarke in general--but it's one of those novels that is a travelogue as much as anything else. I expect you'd have to add to it considerably to create more conflict or whatever for it to be a good film.