I'll be the first to reply then....
Alien - brilliant film. Scared me crapless first time I saw it (I was around 10 years old in the early 1980's....)
Aliens - my joint fave film ever.
Alien 3 - utter shit. They should have let James Cameron do his proposed sequel to his own Aliens sequel (rumour had it that Arnie was going to star in it, off the back of the first 2 Terminator films (also written and directed by James Cameron) then made the top grossing ever films in Titanic then Avatar....). Stupid studio bosses wanted a fresh director with new ideas, and in the end the result was a fick up. In the opening credits it totally dismantles the end of Aliens. And WOW, Sigourney Weaver shaves her head... big whoop. Saw it at the cinema on it's release 20 odd years ago, and never seen it since.
Alien Resurrection - In two minds about this one. Originally hated it almost as much Alien 3, but then put 2 and 2 together and saw the the screenplay was done by Joss Whedon (think Avengers Assemble, and Buffy the Vampire Slayer, and Agents of Shield and the short lived Firefly.) so gave it another go. Joss Whedon himself slags off the film, saying it wasn't what he expected it to be once made. So I can say well written, but then badly made (directed, I forget who by now, but they killed the film off)
I don't think any of them need remaking (or touching up in film visual / audio quality) to be honest. I would see Aliens though on the big screen (I was just a little too young to see it back in 1986 for it's original release), but since I have bought it on VHS (remember them?), DVDs of both the original and director cuts. Then on blu-ray, which does nothing for the visual quality as it used 'stock' film on shooting, so could only ever look 'so good' and DVD did it justice. The 'grainy' look to it adds to the feeling of the film for me.
I know you specifically didn't mention Prometheus, as it has only recently be released so doesn't need a remake (or touch-up), but I was a little disappointed with it. I know Ridley Scott (who directed the original Alien film nearly 30 years previous) and the same producers wanted to put their own take on things, which is fair enough, but in the end left so many things un-answered and tried to cause more questions to be asked - bad move in my opinion. They knew what the audience wanted, and tried to stay away from it.
And as a side note, the Alien v Predator films were crap. Such a wasted opportunity. They could have been epic and ended up rubbish.