If it's entirely cg, it could work, given the material an Alien is made out of (exoskeleton/shit), and how you can pull off its rapid unfocused and seemingly random movements, and how unpredictable it is, that could work. Neil pulled it off so well in District 9 with the Prawns, that I really think he could do some unique shit we've never seen done with an Alien before. The Prawns were choreographed, so well, from their always mouths to their mandibles to their bird like rapid movements, it was all pulled off, where I doubt anyone would question the CG for long aside from, knowing its CG. CG isn't a bad word, I'd love for this to be done, with the Alien.
That being said, if it is entirely cg, I will be disappointed, but not spiteful. It all depends how well they can pull it off, and how well it looks. If it looks like cg, it will be probably something that I'll really loathe. But, if they pull it off with the same detail/finesse they did with the Prawns from D9, I'll be slightly disappointed but mostly caught up in how well the Aliens are moving.
It wouldn't be hard, an animal with fur in CG, will obviously look fake. Something that has an exoskeleton that isn't real, that you don't have to have to have realistic animal movements for, stride, muscle tone etc. can't be pulled off as well as with something that has a hard surface that never existed before. Because you expect an animal to move a certain way, CG animals, dinosaurs, dragons, what have you, don't work well at all. However, the more defined you get with movements, to a pattern, with an animal like a Prawn or an Alien, you just assume that movement pattern is the natural movement pattern of said Thing, because you've never seen said Thing before. Your mind will naturally accept the illusion far more easily, than something you expect to look a certain way.
I understand the hatred of CG, but again, it depends. A CG giraffe and a CG dinosaur and a CG Ape, have less potential to be pulled off, than what they have.
So, I fully expect them to take advantage of this and bring the Alien in ways that haven't been seen as of yet. But that needs to be balanced with practical, if they don't do that, I won't be terribly disappointed, like I said it depends.
After all, the movements of the Queen in Aliens, and the costume of Alien, all had their problems. The suit you see at the end of Alien instantly brings you out of the movie, and despite how brilliant the Queen was pulled off, in a brief movement when its running towards Ripley at the end you get taken out for a moment because its moving faster than its limbs can provide. You have all those moments that are difficult to accept in the series, CG could honestly be a good thing.
