I haven't read the prequels, but have read the main saga. Frank Herbert was certainly a visionary author.

Spicy worms , conserve the water ....

Yes some of the best books I've ever read. I didn't know at first that his son has taken over and thought he really changed his style.

Yes, love the original books, even the movie, and the board game is fun. I agree the other books, I found them lacking with characters I couldn't get into.

I've read the first five of the series. I enjoyed them a lot. Duncan Idaho is a great character. And Idaho, a place where you can find the Giant Palouse earthworm. I did like the sandworms. Interesting mode of transport, as well as so much more.

Dune was my favorite sci fi series. I wonder how much background in religious studies Frank had. It is a very good point now that you mention it, actually he wrote it in such a minor that it was not only believable but completely logical and almost to be expected, bit not in the since of a easily foreseeable plot. It just was how religions go and how people react. It could be a case study for religious anthropologist.