I mentioned this in the Gearbox forums, but I've always wanted an Alien game on the Nostromo to be similar to Amnesia. You're in the ship with a small crew running away from that one alien. A very dark and tense game that also causes dilemmas when choosing course of action. Kind of like the Walking Dead game. Every choice has a major consequence that could get certain crew members killed. And amongst them, as mentioned before, a secret synthetic. One of the things I love about this idea is that the alien would be scary again. That hasn't really happened in a long time.
When I heard Creative Assembly's demo was so good they green lighted the game immediately, I got my hopes up for something like this. But now in retrospect I don't think Sega would have gone for that at all. Now the word "Nostromo" has popped up and I dare to dream :p I think a Nostromo Amnesia game should be a no brainer, so here's hoping they at least get SOME ideas from that formula.