I don’t think it’s accurate to say the series is about tragedy. Overcoming tragedy, sure. The “Tragedy of Darth Vader” was always bogus, the films themselves never supported that framing. I don’t see how the ST changes the saga’s meaning in any way, adds on to it sure but it doesn’t really contradict anything.
I’ll kindly disagree as I find it very tragic as we see a young man lose his way amongst a Jedi Order that suppresses his emotions and doesn’t try to help him overcome any of it. This leads him to having to hide and repress his feelings. All of which leads to the beginning of losing the ones he loves in his mother from his inability to let her go and ultimately his wife as he’s promised what the Jedi refuse to give him by Palpatine as a way of saving Padme from the same fate as Shimi. Even Qui-Gon, the only one who truly believed in him amomgst the Jedi was a significant loss in his life. All of this occurred under the backdrop of a crumbling Republic. By the time of A New Hope he’s a shadow of his former self as he’s become a slave yet again but this time to the Sith and Empire. We slowly see him trying to find his way again when he discovers he has a son and makes a plea for him to join him. Ultimately he is redeemed through the love of his children but not without tragedy along the way.
The Sequels change it from being about the Skywalker family to both the Skywalker and Palpatine family. Making a Palpatine the main hero of the trilogy really misses the whole overarching point of the Skywalker saga as a whole being the story of a family that happens to live in a galaxy far, far away. We can’t say for certain what George would’ve done apart from a few details that have come out but we can be assured it would’ve continued where we left off in a natural direction.
As he told StarWars.com last year for the 20th anniversary piece about The Phantom Menace, “Early on, it was that Anakin had been more or less created by the midi-chlorians, and that the midi-chlorians had a very powerful relationship to the Whills [from the first draft of Star Wars], and the power of the Whills, and all that. I never really got a chance to explain the Whills part.”
His story would’ve followed Anakin’s grandchildren and more than likely would’ve explored his legacy and the consequences of his actions through the grandson who falls to the Dark Side and the granddaughter who follows the Light Side to go along with exploring the more mystical aspects of their family’s existence.
And while the story of family is still there in the Sequel Trilogy it retroactively changes the original intention of it being about a family.
It’s very unfortunate we didn’t get the whole story.