The prequels pioneered CGI in the same way that the OT pioneered new kinds of practical effects. Unfortunately for pretty much every CG thing ever, they were the first to do it or at least on such a scale. With the original they were advancing something that wasn't basically in its fetal stage so it'a gonna hold up better. I'm all kinds of biased towards practical effects mostly cause I enjoy how they're done and the craft behind them. CG is art as well, but building Tube Goldberg machines to do stupid little effects in a movie is just so cool to me.