As for the prequels not having the used future look, well that's the point. It makes sense of how everything was all shiny and beautiful during the republic. The era during the empire was mechanical and soulless with so much of what we saw industrial and military. Generally, I prefer the pretty fantasy world over the gritty used future science fiction world. I think one of the biggest advancements in movies (not just Star Wars) from the 1977 to today is much more detailed set building and more realistic makeup. Maybe even more an advancement than special effects.
Take back the trilogy. Execute Order '77