You could tell the story of the events after ROTJ and make it stand on its own. You could even improve upon the originals (a difficult task, but not an impossible one).
I would argue that it is literally an impossible one because people would never ever accept it as such, no matter how good it was.
I’m not arguing any of the three new movies are better than the OT, but based on the reaction to TLJ, it’s clear to me that no movie could ever eclipse the original in the “fans” minds.