I agree with you. My bias as a visual artist is that I'm such a visual junkie that I'm paying much less attention to the story if the visuals are stunning. Which they are.

And I too was compelled to read the book after the movie. I'm one third into it and to be honest, I think your argument could be expanded into the book as well. While it is true that the central conflict between Harkonnen and Atriedes is much clearer in the book, my central question is this: why should I care about Atriedes? Are they the good guys?

We just have to take the writer's word for it! For all it's worth, they might be just another billionaire exploiter, a softer version of Harkonnens. In modern terms; should I really give a shit if Bezos and Musk poke each other?

This brings me to the second problem: we learn nothing about Atriedes family on their home planet and its local residents. Who are the people they govern? How do they live? Do they like their duke? None of that is given.

To solve both problems we could be shown some scenes of harmonious coexistence on Arrakis, and later on perhaps people begging Atriedes to stay... That would seal the fact that they are the good guys and we (as readers/watchers) should care for them.

I understand this book was written way back and how revolutionary was at its time. However, it is a labour to read and one of the reasons (at least for me) is precisely that I'm not given many reasons to care for Atriedes family. I do care about Paul who is basically an innocent boy (not responisble for the place he was born into), but that's about it. Duke Leto could be just another feudalist asshole, perhaps less of a tyrant than Harkonnen, but still...