It is beyond me ken how anybody could like Dune.
I've run across such odd people on TrekBBS, including the admin who <censored>ed at me for having too-long posts explaining things that other posters had asked me to explain, since I happen to have a copy of
The Dune Encyclopedia, several other non-FH Dune books that were not written by KJA/BH, and was once part of the feud between competing Dune forums where I had to permaban a couple of junior admins for flaming KJA/BH fans and being inexcusably rude to Byron Merritt (Frank Herbert's grandson, who was a member of the forum I ran). It's not that I liked their views of nuDune, but on any forum I run I am so not into allowing staff to bully or harass members.
It takes all interests to make fandom, and I don't go around saying "It's beyond me why anybody could like Harry Potter/whatever it is I'm not into and can't fathom why others like it".
I merely said it is beyond my ability to grasp why people would like
Dune.
The characters are cardboard cutouts & what's with Duncan Idaho? "Idaho" is a name made up by a promoter of Idaho's statehood. It means nothing but it connotes the wild west. It has no place in a futuristic society. Then there are Paul Atreides I, Paul Atreides Ii, & Paul Atreides Il.

That's not how naming conventions work. Giving two people the same number defeats the purpose of numbering them. And until there is a "III,' the naming conventions are "Sr.," and "Jr."
@Zkribbler, if you're going to criticize a literary work, please get your facts correct. There is only one Paul Atreides in Dune (FH's novels, not the ghola-Paul in the nuDune crap).
Paul and Chani had a son, whom they named Leto (after Paul's father, Duke Leto Atreides). This child was killed by the Sardaukar in a raid on the sietch. Later - many years later - Chani gave birth to twins, named Leto and Ghanima. At the end of Children of Dune, Paul is killed and Leto assumes the title of Emperor - and presumably also the title of Duke Leto II (since the planet Caladan still belongs to the Atreides family, it would naturally be passed from Leto to Paul to Leto).
There is no Leto III. I wish I had a dollar every time I had to explain this to some uninformed person on the dunenovels.com forum that the Leto who became the God-Emperor was indeed Leto II, and not Leto III (since titles are passed from (grand)parent to child, not dead sibling to live sibling).
And who gives a crap if Duncan Idaho's last name connotes the Wild West? This is 20,000 years in the future (give or take a century), and nobody but the Bene Gesserit and very specialized historians would ever have heard of the American Wild West. There are people now who still use names that were popular millennia ago, so why couldn't there be a family with the surname of "Idaho"? You might as well complain about his first name being "Duncan" since that's an even older name.
Dune came out in the 60's, a time when feudalism was discredited as an inefficient socioeconomic system. Yet there it is.

This is a socioeconomic system which looks to the past, not to the future.
History repeats itself. We know this. After all, your own country likes to think of itself as an "empire" while insisting that it's really a republic and there will be no kings or emperors, thankyouverymuch.
Stick your finger vertically into sand. Try and move it. You can't. Moving through sand is hard. Yet 80-meter wide worms swim effortless underneath the sand, with no claws, fins or other means of locomotion.

What do sandworms eat?
Ever watched the Star Trek episode "Devil in the Dark" about the Horta? Hortas tunnel through solid rock. Sandworms move through sand. Six of one, half a dozen of the other. What matters is how well the author extrapolated real science, or at least was consistent in-universe.
I read
Dune a half century ago, but if I remember correctly, the prose is bland and lifeless.
Funny, that's how I remember reacting to trying to read Tolkien.
I did enjoy the Bene Gesserit and the bending of space, but that's the only good I can say.
It was the Spacing Guild who folded space, not the Bene Gesserit.