Prometheus brought with it certain expectations that were not met in any form
I disagree. First saying it couldn't decide if it wanted to be stand alone or a prequel, I thought it was more than obvious it was going with prequel considering all the things that we saw.
In May 2009, Fox said that the project was a "reboot" of the Alien franchise, and soon afterwards was reported as an untitled prequel to Alien.[
Scott developed a story that precedes the story of Alien but is not directly connected to that franchise. According to Scott, although the film shares "strands of Alien's DNA, so to speak", and takes place in the same universe, Prometheus explores its own mythology and ideas.
Scott stated that "while Alien was indeed the jumping-off point for this project, out of the creative process evolved a new, grand mythology and universe in which this original story takes place. The keen fan will recognize strands of Alien's DNA, so to speak, but the ideas tackled in this film are unique, large and provocative." In June 2011, Scott and Lindelof confirmed that Prometheus takes place in the same universe as the events of the Alien series. In July 2011, Scott stated that "by the end of the third act you start to realize there’s a DNA of the very first Alien, but none of the subsequent [films]."
Lindelof said that the other parts of the script were strong enough to survive without the Alien hallmarks, such as the Alien creature, which he believed had been diluted by the exposure it had received. He said, "[The producers] were just looking for someone to say to them, Hey, we don’t need the Alien stuff in here. It shouldn’t be about that. It can be a part of this movie, but it shouldn’t be what it’s about." Lindelof said that the film could instead run parallel to the Alien series, and that a sequel would be Prometheus 2 and not Alien, and submitted an idea for how such a sequel could work. Lindelof met with the producers the following morning, and was hired shortly afterwards in late 2010. Under Lindelof, the script diverged from Spaihts's Alien prequel into an original creation.
The history of the project is littered with a lot of back and forth comments over prequel and not, and Scott and Lindelhoff (Lost...go figure), stating that it's ideas were just so amazing!
Fact is, Scott didn't trust his ability make a new property, he attached merely to Alien for effect sake, and I think that hampered.
I think the film could have been better as a stand alone film about the creation of humanity.
I think Scott could have done equally as well with a very strict Alien prequel.
As stated, by himself, he tried to make a new film out of the "same DNA," and it stunk.