All I know is that the franchise couldn't take another "Alien 3 or 4" movie. But then again i'm not sure how many of you actually want to see it continued?
The Alien movie series has always suffered because the execs at Fox never wanted to put any real money into the later movies so kept rejecting interesting scripts left and right for part 3, like the Hicks and Bishop script on a cyberpunk world, and then it was because of Sigourney being so anti-gun part was why part three ended up having no weapons in it (and from memory, part 4 as well, right, with super-Ripley?).
It's all good if people like 3 and 4. Every body likes different things about the series. All that matters is you love Xeno-morphs and things popping out of other peoples chests!
I will love Alien and Aliens forever. As the series grew worse afterwards, I detested part 3 and 4, pretty much because of Hicks and Newts deaths. And 4 being a steaming pile (laugh). As a teen I was mystified why they needed to keep bringing Ripley back movie after movie after Aliens because my interest in seeing more of her story died when Hicks and Newt died (you ba$tards!). Why bring her back? I would have much preferred they introduced new lead heroes encounter them fresh. Kurt Russell. If they needed to bring Ripley back to keep the cash registers ringing, I always felt they should have had her meet and fight the Predators on a space station or alien world to keep things fresh. Why for the love of god did they need to have her back in part three and four I cried!?!
The answer was because she was a producer in the series by then and had say in the Aliens franchise as a whole and she didn't want an Alien movie being made without her. Too bad. I like to think the Alien series can do great if they just had new heroes. I look forward to part five, but hope part 3 and 4 are considered hypersleep nightmares or Ripley being screwed with, being experimented on by the corporation. Hell, then even Newt can be alive. I don't want Ripley being super Ripley in it. Blah! Clones are the cheapest story cop-out ever.
Sigourney was always furious over Fox wanting to make Aliens vs Predator and called the idea stupid. And yes, both AVP movies ended up being pretty bad continuity wise, and part 2 was the death of the potential series, (though the first is enjoyable if you think of it as elseworlds and screw the continuity) but the original AvP comic mini series was awesome, and if they stayed on track with that it could have been great. But for AVP to be great it needs to be set in space or the future, but not contemporary Earth.
Fox has never wanted to put any real money into the Aliens Franchise so had the first AVP moved to Earth instead of a space colony like the comic was. Fox always screws everything over for ALIENS by not ponying up the money. I can only hope in the 2010's, the way we have mega-movies like the Avengers, that studio climate has changed.