I'm surprised they call out the Conclave as an example of a good movie. It's not a bad movie, but the final twist (I'm not going to spoil it) is way over the top and almost absurdly Hollywood.
replies(8):
LOTR is a fascinating counter example; each book is quite dense but was able to be made into a single (albeit long) film. Part of that I think is because a lot of the density of those books is exquisite detailing of the animated natural world of the books; a picture is worth a thousand words may be obnoxiously overused but apropos in this case. The movies seemed to understand the animate life force of the visual landscape and so were able to say a lot visually.
I just don't see Dune: Part II as a true sequel in the traditional sense of the term (though perhaps the literal sense of the term, despite literalism being apparently despised by the articles author).