I doubt there's anything I or anyone else could say that would cause people who don't care for the film to agree that we have "backed anything up" that a film they dislike is good. However, plenty of people did like it, and the heavens remain above us. I will prepare my annotated references later.
I don't think the original script would've been a surefire hit at all. I'm not sure how The Thing prequel did last year, but it certainly was no critical success. A lot of it just feels very much like more of the same to me with the same old alien, and in many ways a lot of fanboy box-ticking - a facehugger! A chestburster! And yes, between the oxygen scene and the chestburster sex scene, it could easily become a cartoon (the first question anyone online would have is, 'how the f**k did she not get killed when the rabid chestburster emerges from the guy who's on top of her?').
Some of what was in the Spaihts draft is fine. And if he did initially set the course back to the space jockey, then he's very much to be commended for that. I've always found his unfilmed work to be great, and a lot of his general framework for the story - Engineers, expedition, Shaw/Watts, David, Weyland - is excellent and holds up well for the final film. But he also had a specific brief when he first came onto the project, which was to make a very standard "Alien prequel". And that's what his script is - just a prequel. Jockey, alien, crash, end. And that's simply not that interesting overall, at least not in what I'm reading here. It might make a Best Buy on-sale item in six to nine months, but it wasn't grabbing anyone on its own the way veering away from the standard tropes does, for better or worse. By refocusing even more on the space jockey and getting away from the alien proper vs. new monsters, as well as keeping characters like David more ambiguous, leaving the question of the derelict a bit more open, I think they opened up much more possibility.
I like Jon Spaihts, and I don't blame him for a lot of this bog-standard Alien stuff. He was given a simple job to prequelize the films, and he did it; his larger pitch, though, the bigger idea of the terraforming, life-creating Engineers was unique and sprawling, it hewed to Ridley Scott's original conception of the jockey and led to the film we got. It's in the nuts and bolts of the script and the storyline that needed to be bolder, and that call only came down to a writer after Scott could make it himself. And I'm glad it did.