I don't think it's nostalgia to enjoy when creatures feel real/organic, which happens when you have a human-operated puppet or costume.
It would be a different story if the computer graphics of the special editions or prequels employed the technology LotR used for Gollum, where they were able to capture an actor's muscle movements, etc. But they didn't, and it shows.
Using "real" effects also meant that they didn't need to fake quite as much for materials or lighting. Wet your Jabba costume a bit and any sliminess takes care of itself. OR, struggle in the computer lab for a while and have what looks like crap (not literally).
This is one of the main reasons why I think Phantom Menace is a pretty okay Star Wars movie. The aliens felt a little more life-like than in the other films; Yoda was a puppet and Jar Jar was done in a similar vein as Gollum. I'm sure others were given a similar treatment, but these two stick out in my mind. Additionally, aliens speak in non-basic, which I like because it adds to some of the mysticism that made A New Hope fun.
Also, I feel that, as steam has said, 4 and 5 are
better films. They're not the be-all, end-all of American cinema, but they're good
. A New Hope I enjoy due to its adherence to the Monomyth, not in a trite way, but in an educated and well-applied manner. Because it wasn't applied haphazardly, but was applied with clear intent and purpose, it makes the film seem less like "generic epic" and more like its own entity. Empire is great because it demonstrates much more of the drama and really showed that Lucas can create a good story, but that the story can be even better when someone else
is writing and directing it. Empire's pacing was very good and it stood well on its own, outside of the other Star Wars films; it left you wanting to know how everything resolves, but it also existed as its own, contained story (granted, it's a story that the good guys lose).