I always liked the idea of the 6 films being Anakin’s story, but after rewatching the OT, it became the clear that that was never meant to be the case originally. If the prequels had been made first, the OT would have been written extremely differently, especially the character of Vader. Vader in ANH is not really at the center of the story. And there’s nothing in the OT to suggest that Vader is a child of prophecy. He was simply a powerful Jedi who betrayed the Order to the Empire, and also had a son and daughter that were hidden from him and the Emperor. His importance to the story came from his high ranking in the Empire, his status as a traitor to the Jedi Order, and his relationship to Luke. It was the prequels that tried to attach much greater importance to Anakin and to make him the center of the story and main character of the saga. But the Anakin we were given wasn’t strong enough to really fill that role. Even George himself at one point said that Vader was meant to be ultimately a pathetic character. A sickly, deformed man in a metallic suit who betrayed everything he’d once stood for and made enemies of his best friend and his own children.
The 9-part saga feels very disjointed now, because the PT and ST both try to redefine the saga in ways that don’t line up with each other or the OT. Lucasfilm has tried to push the idea that the saga is about the Skywalker family as a whole, but in the end, they’re mostly irrelevant to the final outcome of Episode IX.
As Ewan McGregor correctly noted, there is the OT…and then there is everything else. And everything else mostly sucks.