Before Ridley Scott went ahead with Alien: Covenant there was another potential sequel we very nearly got. It was going to be directed by District 9's Neill Blomkamp and would have been a more direct sequel to the existing franchise than the prequels being made by Scott. While it's currently looking like the movie will probably never happen, if it did, it appears that both Sigourney Weaver and Aliens director James Cameron were on board. According to Weaver...
Following the release of the "sort of Alien prequel" Prometheus, there was some question about where the franchise was going to go next. Ridley Scott was, at one time, interested in doing several follow-ups to Prometheus, but then an interesting dark horse entered the fray when it turned out Neill Blomkamp had an idea for his own Alien sequel. The project would have reportedly discounted the last two Alien films and would have been a direct sequel to James Cameron's Aliens. The movie would have reportedly seen both the return of Newt as well as Michael Biehn's Hicks
For what it's worth, Sigourney Weaver's comments to The Hollywood Reporter make it sound like she hasn't entirely given up hope of making the movie. It seems that everybody is pretty busy right now. She and James Cameron are making 57 Avatar sequels and Neill Blomkamp has his own projects that he's working on, so it's certainly not going to happen soon, but could it still happen?
While it's certainly a long shot, a lot is changing in the future, so maybe there's a chance. Fox will be owned by Disney so they'll be the ones making decisions about the future of the franchise going forward.
In addition, the recent Halloween sequel pulled the same "soft reboot" idea in the way it ignored the previously made sequels, and it has scored big at the box office in doing so. I'm sure every studio in Hollywood is wondering what franchises they have that could do something similar, and Alien is certainly one of them.
The fact that both Sigourney Weaver and James Cameron are on board the idea will certainly help. Cameron is currently making several sequels to his record-breaking Avatar franchise and if he makes Disney as much money as they are likely hoping, he may have the ability to make some other things happen with another big franchise.