Truthfully I think the OT will probably never be topped. It was lightning in a bottle that caught Lucas at his peak when he was a very different person and had just the *perfect* mix of other collaborators at the exact right time.
Disney could make another 20 Star Wars films and probably never seriously top the originals. Lets look at it.
A New Hope - Was mindblowing special effects that revolutionized everything. No one had seen *anything* like that before. As a a result it's pretty much impossible for another Star Wars movie to have *that* kind of impact. This was a cultural milestone that defined the late 1970s. Can't be topped in other words.
Empire Strikes Back - The perfect Star Wars movie; it made the bold choice to be serious about the subject matter and stop with the "wink, wink, this is for kids" stuff. It elevated the themes to a nightmarish level. The wonderful, masterful introduction of the Yoda character as expanding the "Force" concept into a zen-religious philosophy that gave the franchise tremendous spiritual gravitas that connects to people in a deep way. And then you have one of the ultimate plot twists in movie history that changes how you view everything in the saga. Every beat in this movie just works, every subplot works.
Return of the Jedi - OK, not perfect. The 1st half has some sillinesss/meandering and the Ewoks were a shuddering foreshadowing of what would come with Lucas becoming obsessed with kiddie silliness to counter balance the darkness that was creeping into the saga. But still, what needs to work in this film resoundingly works -- the Emperor/Luke/Vader scenes are the best in the trilogy and offer a tremendous emotional catharsis by the end. Also the Emperor Palpatine was a wonderful addition to the trilogy, you know that sinking feeling when you realize as evil as you thought Darth Vader was .... he's a puppy dog compared to Emperor. *That's* scary. Because so much good was set up in ANH and ESB, ROTJ can cruise by on that and it finishes with a thunderous slam dunk.
I didn't have high expectations after the prequels for Star Wars honestly, TFA was about what I thought it would be ... a movie that would return the fun, "rag tag characters who care about each other" type dynamic to the trilogy and lay off the overly cartoony fetishes that Lucas became obsessed with. And a ton of nostalgia. That's pretty much exactly what TFA was.
In a way the OT, especially Empire, is a bit of a curse for Star Wars. Once people got a taste of Star Wars being serious, pyschological, and philosophical to another level that Empire brought to the table ... it's been impossible for any of the sequels/prequels to live up to that level. If Star Wars had stayed kind of the silly, not-so-serious jeez-whiz adventure film that was A New Hope, it would be a different issue.
