The 'failure' of the prequals is only in the eyes of the die-hard fans. All three still rank on the top 100 all time worldwide box office grosses (TPM #13, ATOC #66, ROS #33). If that's failure or in need of 'saving' George Lucas laughs all the way to the bank.
If that's failure your demand for 'success' is quite high.
The 'failure' in your eyes is most likely due to the fact that you had so high expecations to the prequals that it was impossible to live up to them no matter how good the films were. I know I was. You're dissapointed that Anakin wasn't an adault in TPM, you're annoyed over Jar-Jar Binks etc. It's called a hype and a word of advice: Get over it.
I learned to appreciate the films after I realised that what I had was childish dreams of delusion of what I hoped that the films should have been. I've seen this repeated over and over and over on various boards (Stardestroyer.net I'm looking at you) and it's the same pattern each and every time.
The prequals are not in need of saving, or for that matter in any way shape or form a failure by any rational definition. The only thing I ever would change is replacing Natalie Portman due to her wooden acting in ATOC, particulary the romance scenes. They're cringe worthy due to her acting (or really, really good if she were portraying a girl with very low self-esteem).
Again, you're invoking all the stuff I've mentioned before out of what the Star Wars prequels, and all too many films of that millenial era were, being a cultural trauma. "It's must be good. Something must be wrong with me", "It just seems like they're bad because of nostalgia", "It seems bad because I had my own ideas of what happened before the trilogy", etc, etc, etc. I don't stay quiet for that anymore, because it's people putting themselves down and making excuses because they want so badly for their feelings to not have merit, because if they do then it means something attached to something they care about stinks. That should pretty well show the fact that people are
not going *hurumph**hurumph* wanting these films to be bad, and that's why they think they're bad. Everyone wants to hold this very wide eyed optimism. Had the films been good, the fact of the matter is that people would have accepted them without a peep, George Lucas would continue to be a hero, and nothing would be an issue. You may have a bit of criticism depending, but no more so than you did of "Return of the Jedi" or "The Last Crusade"; a different sized fish in a different sized pond.
The fact is, the prequel films were not at all good films. Red Letter Media thoroughly skewered them and explained in detail the exact reasons for their failures in quality. They just were not good films. The reason they made ungodly amounts of money is, in order: "It's finally coming and it has to be great because it's Star Wars", "It has to be better than Phantom Menace and that first film must have just been a fluke and just had to set stuff up, and it'll be great from here on out, and it's Star Wars", "I've heard it doesn't suck like the first two and is actually good, and it's Star Wars". And fanboys without merit of the kind under attack by statements such as yours are
not the ones critiquing the prequels: they're the ones who went to them gleefully and thinking they're great achievements.
And this topic is not just about the prequels, but about the whole of the Star Wars intellectual property, George Lucas in relation to it, and everyone else in relation to it since about 1997. You saw things start to collapse. Before then, it was this thing people just loved and which was praised, with George Lucas revered and with a number of popular and well done books and comics and so forth. Then the "Special Editions" started to come out, and everyone thought that was cool. But then George Lucas made it known that those were now the official editions and that the theatrical cuts would no longer be released on video, and he essentially disowned them. That was the first problem. And then "Phantom Menace" came out and was significantly not a good film. And then everyone waited around for "Episode II", shrugging off the first prequel as bad just because they had to set everything up. And "Episode II" stunk. And then everyone waited around for "Episode III" and settled on that being good enough. And over the course of all that, you had that perfect community of support schism, you had George Lucas lose his reputation, you had Lucas tell his audience to get a life (though they gave him his) and that he preferred the way things were and that it was for kids (even though he fired people off the set of the original trilogy when they said that) and alienate his audience with his behavior and attitude towards them, and things got a whole lot more complicated. The prequels are just part of a larger thing; it's also his reaction to the criticism and ways of shirking it off, and his treatment of the original trilogy.
What George Lucas has done in reengineering the original film trilogy is unprecedented. You have had directors reedit their work, notably Francis Ford Coppola with "Apocalypse Now Redux", but you have never seen them do that and then not allow the release of the original, theatrical version of their film anymore, disown it, penalize even people who own original film reels, keep their theatrical cut from the National Archives for preservation, instead trying to submit the reengineered version of their work, vow not to release the original version, etc. Had George Lucas done a reengineered edition (I keep saying that word, btw, because it's more complicated that just reedit or reimaginged) and release it alongside official releases of the theatrical versions of his film, there would be absolute no issue whatsoever. Those "Special Editions" would still be open to criticism, but it wouldn't be such a head-to-wall fury of wondering why we cannot receive the films as originally done and in the form which affected the culture, and are being forced with that as the only option. There is no overstating how upset that has made people with George Lucas because he gave people this thing so many people came to really like and care about, and he took it away very selfishly. And it comes across like he's just purposefully being mean.
You don't get to do that. Once you release something, that belongs to everyone else. You can do another version of it, but you can't take away the version you released. If Da Vinci came back somehow, he would have no right to take the Mona Lisa to paint over it. He would have a right to do another painting of that idea, as Munch did with "The Scream", but he would have no right to do that with the original work once it's released to civilization, and especially once it becomes something in the core of culture. Lucas could have done what was done with "Apocalypse Now Redux" or "Superman II: The Richard Donner Cut", releasing a director's edition of Star Wars along side the theatrical edition. But he has not, and that is a major issue. And the original prints are very likely crumbling to dust with age, if not directly cut permanently for the "Special Editions", and he refuses to do anything about it, and he refuses to allow the National Archives to preserve the original trilogy in it's actual form. That is very disheartening from the man who once railed against colorization for damaging the original films to appeal to shallow modern sensibilities, and who obviously loves film. I would say it comes from a sensibility people have where what came before their time is like holy writ, permanently existing and to be untouched since it's always been the final product in their mind, and whatever came after their time is just superfluous BS that can be changed since they saw it come into being, and since they saw it created then it must be malleable as when it was being created. That's what I would ascribe Lucas' treatment of the original trilogy to. And it's frankly childish. In reality, those things before Lucas' time and it his younger days, in the 50s and 40s and 30s, have just as much merit as what came in the 70s and 80s and 90s and onward. They are just as much a final product, and just as much a malleable product. If the films of the 50s, 40s, and 30s should be left alone as seems to be Lucas' opinion, then just as much should the films of the 70s, 80s, etc be left alone. And if you plan to do something about it to reengineer it, then you cannot make that the only version that exists.