George Lucas, when being interviewed, often had a habit of talking about ideas he had for future Star Wars films or backstory he had developed that hadn't made it onto the screen.

Take, for example, this quote from a 1977 interview he gave to Rolling Stone magazine:

"It’s about Ben and Luke’s father and Vader when they are young Jedi knights. But Vader kills Luke’s father, then Ben and Vader have a confrontation, just like they have in Star Wars, and Ben almost kills Vader. As a matter of fact, he falls into a volcanic pit and gets fried and is one destroyed being. That’s why he has to wear the suit with a mask, because it’s a breathing mask. It’s like a walking iron lung. His face is all horrible inside."

While some of the the details certainly changed by the time the scene was shot for Revenge of the Sith 20+ years later- like Vader and Anakin still being completely separate characters - this is insight you wouldn't have from just watching the movie.

In that same interview Lucas even hints at what would eventually happen with the prequels: "One of the sequels we are thinking of is the young days of Ben Kenobi. It would probably be all different actors."

It would be great if George Lucas would have hinted at Jar Jar Binks in some old interview from the 70s. This is how I imagine that quote might have gone.  

Sadly I haven't found anything like this for real, but maybe something will turn up someday.