It's often said that the Star Wars idea of a lived-in universe was a unique thing. And that from models to set design, everything had to look used. I think that this carries through to the SFX, which were assemblages and mixes of several real sounds, banged together with analog equipment.

The new trilogy never quite "felt" right, there was always this disconnect of the visuals and the sound effects. I remember seeing a video going over how they built up the sound effects for the pod racer scene and, while it was interesting, I never really felt like the sounds fit the film in the same way the sounds did with the original films.