They just have to step back and write something that pulls it all together. This ISN'T NEARLY as difficult as everyone is making it out to be.
I love her, but Sigourney f**ked it up when she didn't want to do ALIEN 5 on Earth and yes, killing of Newt and Hicks was a mistake narratively. But neither one of those scenarios are unmanageable provided the writer steps back and FOX thinks through the next FEW sequels and not just the NEXT one.
That's the problem. That has been the problem from the get-go. And contrary to ALMOST EVERYONE'S belief - it's not really even remotely unsolvable. Especially with where the story is now and since they are proceeding with another prequel that can easily tie into what happens later.
There is no need for a retcon. They need to come up with an all encompassing story and having a HOMEWORLD-type planet tied into it is the step they were always missing. The other big picture, missing element which BLOMKAMP's film seems to want to explore is what the COMPANY will do with the Alien if they get it.
If you'd rather not step things up because you'd rather have Hicks back, that's just childish and it isn't whats best for the series. Neither is ignoring multiple sequels. You want to say their deaths are poor writing - ok. But fixing it by retconning just makes a bigger mess.
This should have nothing to do with retconning or Alien 3 at this point. That was 4 films ago. Going back there, to that space, just because you want to, is bizarre and ridiculous, IMO anyway.
They just need to step back. Look at what has happened, and ask "what do we need to do to pull it together?' And then just yarn it. It's really NOT difficult as people have led themselves to believe.