Did John Williams know that he was writing sacred music for an entire generation when he started on the soundtrack for Episode IV?
I'm no die-hard fan. I've seen the movies, I've read a few of the books, and that's about as far as it goes. I'd be the first to agree that Episodes one through three pissed away a lot of the vision and majesty, to the point that I've occasionally considered inventing my own backstory to replace them. I can also admit that even the original three movies, when examined closely, are a bit corny. But still, there's something about the main theme, and the Imperial March, which stir the spirit. It's such a BIG universe, full of habitable planets and half-explored at best. Mighty (and not so mighty) starships ply the lanes between ultracivilized planets, but just off the beaten path are forgotten ruins in the jungle and cities hovering in the clouds. You could see something you've never seen before every day of your life. It's a universe made for romance and adventure, and when the music sounds, it brings all of that with it...
Frankly, if Lucas is done with it, I think he should let other filmmakers use the background. Shared universes are well-known in written fiction, there's no reason why it shouldn't work for movies too. Hell, why not let it be a serial, like the 1930's serials that inspired it? There are an uncountable number of fan-made shorts, why not round up the makers of some of the better ones and say, "here's $25000 and an advisor/liason, make me a 15-20 minute pilot, and if it comes out OK, you'll get to keep your storyline going."
Of course, that will never happen, but it's a nice dream. Now I need to go read Brian Daley's Han Solo trilogy again.