Shakespeare wasn't Shakespeare until years later; they were extremely popular mass-entertainment, yes, and there's a certain genius to them, but how much of that was recognized in his own day?
Not that I'm suggesting people will look at the Star Wars prequels in a couple hundred years as masterpieces...
Anyway, the Star Wars Prequels as modern myth has/had the potential to be new classics, but ultimately failed in some critical areas.
Also, people would likely still be criticizing Lucas for his unending need to not just perfect, but remove as much as possible the unfinished version.
