This is quite unfair to Lucas. Star Wars was a groundbreaking achievement at the time, and it was due to unique vision of Lucas. He should get credit for that,

This is quite unfair to Lucas. Star Wars was a groundbreaking achievement at the time, and it was due to unique vision of Lucas. He should get credit for that, even if he later made some mediocre movies and angered some fans. I know Star Wars is said to have been "saved in the editing", but it is quite normal for movies going through many edits and to correct issues in postproduction. Many successful movies need re-shoots after scheduled shooting ends. How many reshoots did Lord of the Rings need? More fundamentally, the director does not just direct the actors, he direct all roles like editor, cinematographer, sound designer. If he select great people and get them to do their best work to realize his vision, it shows he is a good director. It doesn't mean that a successful result is "because of others". At least not any more for George Lucas than for say Orson Welles. Sure the prequels were underwhelming, but the newest trilogy was just as bad without the involvement of Lucas. This just shows how well the original trilogy was written - we don't really need to know the prehistory of Darth Vader or Han Solo and we don't need to see the characters return again. The original story arch was perfectly told and satisfyingly resolved.