Yeah, it sounds amazing, but I think it would have been a disaster. Jodorowsky never actually read Dune, and he had the grandiose, completely impractical ideas: Salvador Dalí as the Emperor, his girlfriend with no acting experience as Irulan, Jodorowsky's son who also had no acting experience as Paul (the main character). Jodorowsky saw himself more as a God than a Director, IMO.
I watched the documentary in a small screening a few years ago and the project sounded incredible... It wasn't Dune, not the Dune we've read, but amazing nonetheless. I definitely recommend watching it (be forewarned, Jodorowsky's english is atrocious). So many interesting stories about that movie:
Some of the design work and the people that worked with Jodorowsky actually went into Alien. I mean, Giger, of course, but also Dan O'Bannon a few other people.
He actually got Dali and Orson Welles to say yes to the project. Dali wanted to be the most expensive actor in history.
The story with his son borders abuse. He basically wanted to convert him into the Kwisatz Haderach and made him go through a very tough training for years.
Personally, I did enjoy David Lynch's version and even the tv mini-series they did (back in the late 90's?).
https://www.youtube.com/watch?v=jg4OCeSTL08