I personally hated the redemption of Darth Vader in ROTJ back in '83, because that was something I thought at the time that just didn't jive with the Original SW movie that I grew to love. And as much as I was an OOT fans growing up as a kid, SW '77 was the King of all movies to me, and ESB/ROTJ were just more stories of my beloved characters, but never lost context of what the story was in 1977.
So you are correct that fans at this point can go either way, and I say to you don't worry, the Darth Vader story crowd will be a niche fanbase. Now that will be a loyal one, but the amount of SW fans who actually love all 6 movies will be very minor because I just find it hard to believe that a majority of people are going to love 6 movies when atleast half of them are average at best.
If the internet was around in the early 80's, I believe the fanbase of SW'77 fans and OT fans would be split, and we would be arguing the same stuff now, but as I said, the difference is SW '77 was never touched back then, so nobody would be arguing about getting SW '77 in proper form as we do now. But I know there would be a huge fanbase of SW '77 fans saying that Darth Vader has no business being Lukes father, let alone Leia's father too.
But I began to change through the years and actually began to like the story ROTJ presented with Vaders redemption. I still think ROTJ is an average movie, but I give kudos to Lucas in ESB & ROTJ for taking the saga in a different direction then an actual retread sequel that most studioe put out, and he tried to keep it fresh with each new movie. I believe Lucas tried the same stuff with the PT, as he tried to keep it fresh too with something new in every story instead of what we always thought, but I think eventually you do it with too many movies, and you eventually alienate people by drastically changing it, and when you look at the first movie from 1977, it is TOO different, and loses its luster from what you fell in love with.
I will contest til the day I die that the PT was not for everyone, whether it was done right or not. I still believe there would be a good amount of OT fans who would never gravitate to the new characters, cause old faithful Luke, Leia, and Han weren't there to save the day as they did in ROTJ. I believe the whole tone of the PT being a bit darker and more grey when it comes to the story and the characters was going to turn people off too, because the OT movies are ultimate feel good movies where everything is in black and white. In some ways I think Lucas was set up for failure from day one, cause a prequel trilogy of 3 movies is really a big roll of the dice.
I read an article where Lucas realized in 1988 that if he made the PT, it could then be the story of Darth Vader, or the character arc, and that is exactly what 1-6 is, a character arc of Anakin Skywalker, but as we know the OT story, especially ANH really doesn't tell that part of his story very well cause it was never about him. So what Lucas ended up doing is really make fans who truly love the character of Darth Vader really happy with the 1-6 order, and everyone else likes parts of the movies now.
So the genius of the SW saga is its biggest flaw, it isn't one continuous story, cause it never was from the start, but you have so many different fans who love certain parts of the movies, like certain parts, and hate other parts. So in one way, we are all SW fans, even Gomertonic, but in another sense, we are so different only because the story has changed so much.