Originally Posted by
George Cumby
What he said.
Episode 4, when it first came out, was just a mash-up of: The Hidden Fortress, 12 O'clock High, Spaghetti Westerns, Pirate movies and Flash Gordon.
Lucas was just trying to capture the magic of afternoon matinee serials of his childhood. Which he did but only because his editors, including his now ex-wife, saved the film.
But because his ideas were half baked, he didn't have a real idea what came before or after. That's why the EU took off, other writers had ample room to work. This is why you don't see a LOtR 'expanded kingdoms', Tolkien had already done the work of world-building.
At least the prequels had a coherent, if poorly executed, plot arc. The sequel trilogy became this incoherent mess because of the director's bitch fight between Abrams and the other guy.
The flaws of episode 7 aside; rehashing old plot arcs, there was some room to work. But the other guy totally messed it up.
I haven't read them, but true fanboys report the Timothy Zahn books would have made a far better sequel trilogy.