Achilles Heal?

***MAJOR SPOILERS, BE WARNED*** Prometheus is a movie which contains a plot that is contingent upon the idea of it being continued within a subsequent film. It does not stand on it's own like many classic sci-fi/action/thrillers do. Films such as: The Matrix, Inception and Alien. Like Prometheus, all of these movies created their own universe/set of rules. They opened up very interesting discussions (Alien, the least out of them). Unlike Prometheus, they all contained plot/thematic resolution. All of these movies screenplays had an intensity to them and this intensity, after it peaked, all simmered down to a resolute final scene. In The Matrix, Neo becomes the one, and informs the machines that he will inform all of their captors of a world without boundaries. His threat ends with putting the next move in their hands. In Inception, Cobb finds a way out of the depths of the mind and is reunited with his family. He tests his reality but is distracted and never sees the result. The audience is left to wonder... Finally in Alien, Ripley escapes the Nostromo but has one more surprise encounter with the alien. She manages to survive and goes into cryo in the lifeboat with the "hopes" of being picked up along the way. All of these films ended. They resolved their major themes yet left enough room for expansion. These films were never dependent on the notion of a sequel. The option was there because there were still things that COULD be explored. What challenges does Neo face in his future against the machine race? Is Cobb in reality or the mind? Do others perform these mental games? Does Ripley get rescued? Does anyone find the derelict ship? Where did it come from? Prometheus aimed to open a discussion about a race of beings which create various forms of biology, and apparently humankind is possibly one of them. By the end of the movie there is no resolution AT ALL. There is no sense of decompression for the audience. The intensity, the questions, the anxiety is all but still rolling through the very last frame. A movie which ends like that, with the main protagonist leaving for an alien world for answers to all of the films major themes, is dependent upon a sequel. This is NOT ambiguous, it's outrageously open ended through a "to be continued" cinematic move. The film could have had a million different endings. None of which needed to be connected to Alien whatsoever. But IN MY OPINION, the film needed to END, and by end I mean with some solid resolution. A well crafted ending, resolves a few of the major themes to an understandable level, while also not answering EVERYTHING as to allow the possibility for further exploration. I understand that RS has mentioned the idea of a sequel for years now, and even recently has expressed that he wants to do one... but I think the film would have been STRONGER if it COULD stand on its own as well. I am not necessarily upset with the ending, however I feel it is simply cliche, commercial and not intellectually stimulating. I feel that the ending is Prometheus' achilles heal. Thoughts?