Alien is a franchise that started in the 70's. It has had two good movies, the first and second. The others aren't without their charm, but don't reach the same standard. My idea for a sequel is far different from what has come before, not a slasher movie in space, nor an action film.
The movie would primarily take place in a Weyland-Yutani Corporation boardroom. In it we would see an executive laying out how much money and other resources have been wasted trying to get their hands on and research the Xenomorphs. Showing how many spaceships have been lost, how many families of dead crews they have had to pay off, how many research facilities have been destroyed, and importantly how they have nothing to show for all of it.
It could get into how they initially had military funding for some of this, but they have pulled out for it seeming to be a dry hole. How when they first started there Xenomorph projects they thought it would quickly yield military and consumer products, but has given nothing useful. How the medical angel mentioned briefly in the second movie has been a complete nonstarter.
You could even have moments of levity, where other executives bring up various research facilities, only to have it pointed out they they have all been renders destroyed or unusable by the Xenomorphs.
Perhaps this would be too dry for the average movie goer, but it would be something new and different for an old franchise.