How would AJ's DUNE have gone down in history?
If Jodorowsky actually made Dune I don't think the SFX would have been as good as he was envisioning and it wouldn't have been the Star Wars/Jaws/Godfather blockbuster of the 1970s. But I think that among his fans, enthusiasts of underground films or hardcore sci-fi readers it would have been considered the best sci-fi film of the decade if not of all time.
The torture of Duke Leto, the artwork of Giger, the casting of the Baron, the Emperor etc. would have made this an instant classic. And the ending pre-dated "V For Vendetta," if not "Spartacus."
It would have definitely altered the course of subsequent movies like Star Wars and Alien. George Lucas might have actually had to come up with an original idea for once in his life.