Ripley's story ended when she sacrificed herself. Ripley 8's story could end with Alien Resurrection : the movie had a kind of "end of the cycle" quality.
But if Weaver (such a great actress) wants to be in Alien V, the easiest way of doing it is, of course, to continue the story, with a kind of ultimate confrontation (conceptually speaking, because I'm quite sure many think that the "ultimate confrontation' would look like a prolonged equivalent of the scene in AvP where there are thousands of xenomorphs against several predators on the summit of their pyramids
).
The problem being that conceptually speaking this particular brand of alien has been dissected in four movies, and Resurrection has already done the "let's mix aliens with human and the reverse".
It's a general problem for a fifth Alien movie : it can't be content with the strict application of an already known recipe. At least for a demanding Alien enthusiast like me. When I read many comments here and elsewhere, I wonder if I'm the only one who would like a good (or very good) movie in the absolute, not in terms of "it satisfies my Alien fan instincts".
There are other possibilities, for instance : 1/ a new timeline (so a retcon) with Ripley - there are problems with that ; 2/ no Weaver, and a new story, that can happen any time between the events after Prometheus and the future of Alien 4.
One of the problem with the first possibility is the fact that Alien 3 has
a very strong end for the character of Ripley. It makes the initial three films, well, a trilogy, that, even though it was not conceived as such, has coherence in the end.
Of course, there are the complaints about the death of two beloved characters. You've seen GOT or read A Song of Ice and Fire, so it should not be a problem any longer.
It's maybe too much to override two movies - the third and the fourth - for the fifth, no ? It would be arrogant, above all if the new movie is clearly not a masterpiece.
But it's a period where this kind of thing happens quite easily, so I would not bet. The most important thing is to have a great movie, with its spirit and individuality...
(You will have understood I'm quite skeptical in what regards the power of some concept arts on many fans...).
