After reading the description I'm thinking this won't be a horrible loss.
I'm a huge Alien/Aliens fanboy but the last thing the franchise needs is more alien types running around. Yes, it's established that the alien inherits traits from the host but this game looks like it was drifting way too far down the path of "let's come up with some really cool new aliens" just for the sake of creating cool new aliens. Bah.
I mean, a chameleon alien? Seriously?
Well, as the developer comments note, they couldn't really just limit it to what people knew. They had to add some new types to provide some level of dread to players fully versed in the setting. It's not at all clear if they went overboard in that regard.
My biggest excitement was not so much for the setting as it was Desslock's reference once, after seeing some early aspect of it, that is was going to be a very tactical RPG in terms of combat. Most recent western RPGs are jumping all over the action type of combat so it would have been nice to see something different.
But as I said above, somehow the development time seems to have been much longer then it should have been. I'm sure the combination of how long it was taking, the uncertain aspect of how well this kind of RPG would do, and Sega's own financial problems all combined to doom this project. I'd bet money that if it had been an RPG in the vein of Fallout 3 (i.e. first person action) that it would still be in development.