I agree. Dealing with the fact that most players will expect an encounter with the xenomorphs is hard to avoid. A way to get around that in a campaign could be the questions I posted on page 3 in this thread. Another, perhaps simpler way, could be to consider three core themes in the Alien franchise:
1. There is a corporate conspiracy. There are secrets and hidden agendas within the Company. They will have an impact. People will do things because they are a part of a bigger picture.
2. AI matters. Androids have agendas of their own, perhaps connected to a higher corporate level. Or just to a deeper understanding of things. It’s worth considering that androids see things profoundly different than humans. They might have a deeply moral programming - or a programming that makes them able to act beyond any kind of human standards. They are not human, even though they might seem to be.
3. There is alien life and it’s partly unknown to mankind. In a campaign it could mean encounters with the xenomorphs that are described in the basic ruleset. But that is the expected. You could also explore the unknown in other, more creative ways. I expanded on the grand vision of Gigeresque biomechanics in this thread: viewtopic.php?t=4968
I hope those ideas are enough thought provoking to make it possible for others to go far beyond the expected - and still stay very true to the core ideas of the Alien universe. To me, H. R. Giger is a true visionary. We can all harvest his art for new ideas. Alien is something far more than a Disney staple monster brand.
I would say that an Alien campaign could explore any of these core themes - just one or two or all three. There are also other themes in the setting, but I don’t see them as important as the three above. Seeing and defining the core is, I think, allways a good start.