He basically combined the father skywalker character vader betrayed and murdered quite literally in star wars 77 with Vader in empire strikes back.
The deleted scene with red leader for instance had him telling luke how he met his father and how he was a great pilot, when the scene was released the dialogue was removed.
I think the beginning of this epic and tragic story concept began in Lucas mind during the filming in return of the jedi, Vader became a much deeper and complex character when he was written as the heros father thats stuff right out of a greek tragedy.
When he chose that angle in empire it changed the whole course of the story.
Still i don't think he ever definitively came out and said darth vader was the hero of the whole saga.
Though he may have already been leaning towards it.
Before vader being the father star wars was a story of rescue and luke joining the rebels and revenge. Luke would have gotten revenge on vader for his fathers murder and kenobis death.
Then Lucas later determined jedi don't seek revenge. And now that vader was the father instead of killing him he sacrifices himself to save him, to redeem him.
As far as i know star wars was always the adventures of Luke Skywalker as the title was on all the original books, from the adventures of luke skywalker. Luke Skywalker was the hero, he was the audience's avatar and passport into the world of star wars. The alter ego of the audience. I don't know how anyone can identify with vader since his fall to the darkside makes zero logical sense in revenge of the sith.
How could anyone have sympathy for him, especially in the form of a Hayden Skywalker.
There was an emotional response from the audience when anakin died in return of the jedi, because without his mask on he was this kind old man who was frail looking, and he died and some people cried.
I found even as a kid the heroic theme being played over his funeral pyre scene to be incredibly powerful, the force theme. Then as a redeemed anakin joins his friends yoda and kenobi, under the ewok music it was truly moving. Although everyone now says they hate yub nub.
