Thing is, the Alien contributed to create the generic movie monster features. It's since Alien we have skinny monsters (hell, there are a lot others that have a visible ribcage; it's fairly common now, although it's undeniably a cool feature) and all that stuff. And not in case. The greatness of Giger's design inspired countless works after it and a lot of designs "borrowed" traits from it. The A:R Aliens unfortunately suffered from this because, instead of being associated to the legacy they were continuing, they were associated to other movie monsters that borrowed some design choices from the first alien, ending up looking similar in some details.
But the A:R Alien still features the most striking features of the original Aliens (bar the biomech, still present but in a far lesser quantity), alas the long, stretched head, the eyeless feel, the visible bone inside the semi-transparent dome, the shredded cheeks, the metallic teeth, the inner jaw, the back tubes. Something not quite common in other movie monsters.
Oh, and I like both Pumpkinhead and the movie it stars in. Winston did a great job with it.