Lynch understood what the problems of a direct adaptation would be. An example would be the Weirding Way. One would have to invent a martial art that both looked fresh on the screen (new, different) and was also simultaneously overwhelmingly powerful. This is perhaps nigh-insurmountable (I dunno, clone Bruce Lee, but also raise him with a lot of cinematography experience, then have him design another Jeet Kune Do which
looked impressive through a lens). Lynch opted for the Weirding Modules, which still provided this surprise advantage against the Sardukar terror troops
and tied back, thematically, to Paul being the fulfillment of prophecy.
He understood that millennia of feudalism would make for a psychically claustrophobic atmosphere, that the avoidance of the thinking machines would necessarily birth the creation of humans who might have visibly different traits ("... the lips acquire stains ...") from the strain of being human computers. He understood that voiceovers were appropriate because, to survive in such an environment, you must constantly be thinking about what other minds are thinking, to remain steps ahead.
Finally, Lynch understood that the dialogue must be larger than life. I heard a trailer for the recent one and I swear, some of the dialogue between Paul and Chiani sounded like Avengers-era quippy Whedon output.