Oh, undoubtedly the special effects would be considered earthshaking. The OT was one of, if not the, most visually impressive films ever in its own day, much less movies with decades more advanced techniques. People would be awed by them, no doubt about that.
The Sequels may get a bit of backlash for embracing "reality is brown." The OT and prequels had a brighter palette, especially on the aliens where you had numerous green, blue, red, and yes, brown skilled aliens. However, the sequels basically had only orange or brown skinned aliens, usually wrinkly and almost always bald for some reason. We're used to how brown worlds have become (This, in turn, seems to be a backlash against the massive tendency towards making everything Teal and Orange that came before the brown world trend in film) but exported to the whole trilogy at once for the first time, people are certainly going to notice the sudden jumps to brown-ness.
