You probably already knew that William Gibson wrote an unused screenplay for the third Alien movie. But did you realize how much the first couple of Alien films have in common with Gibson's work, and in particular his Sprawl trilogy? Find out where alien parasites and a cyberpunk classic connect.
In response to this post on the possible future of the Alien cinematic universe, commenter lightninglouie noted the unexplored similarities between the movies and William Gibson's Sprawl series. The similarities aren't just the shared reference point of H.P. Lovecraft, though. It's that, despite their wildly divergent subject matters, both are dealing with questions of how we respond to, often incredibly powerful and influential, but essentially non-human entities. And that has some interesting implications for what the next sequel might look like:
One thing I learned while reading Gary Westfahl's monograph on William Gibson was that in his adolescence he was a huge Lovecraft fan. And in his Sprawl series, as well as his later, less-cyberpunkish novels, there is an enormous sense of existential dread, that the heroes are just pawns in the schemes of vast, unsympathetic entities that may not even be sentient as we understand the concept — AIs, alien intelligences, government agencies, megacorporations. The overlap between Alien and Neuromancer is more than just aesthetic (Gibson's "dirty sneakers" future) — deep down, they're dealing with very similar subject matter.
It seems to me that a politically aware filmmaker might recognize the parallels between big business and Lovecraftian space terror as embodied by the Engineers — in both cases it's unclear how malignant the enterprise is, if there is some sort of master plan or everything is just proceeding as a series of colossal SNAFUs. Both Weyland-Yutani and the Engineers value them for their lethality as living weapons — though the Engineers presumably used them to "clean house," whereas W-Y sees them as a military-industrial asset. The latter aspect is something an Alien movie really needs to explore. If there are Colonial Marines, it can only follow that there are colonial wars — and there may still be global conflicts back on Earth, which as far as we know is not even unified, as in Star Trekand countless other space operas.
One possible re-entry point into the Alien universe might be to start out in the middle of some internecine conflict on an established colony world (as opposed to a "frontier town" like LV-426), some sort of third world/Cold War scenario with local factions struggling to maintain control as larger corporate and governmental organizations strive to influence the outcome. Either the fighters stumble across a crashed Juggernaut or a hidden Engineer facility, and all hell breaks loose, with W-Y (or some other sinister entity) paying close attention. Or W-Y releases the Aliens on a rebellious colony as an experiment (or a demonstration). If you wanted to play up the political subtext, pointing out that humans aren't coexisting peacefully in this universe would provide a much larger justification for the nearly-exhausted "Company Wants Aliens For Bio-Weapons Divison" subplot.