I disagree about the whole "It's the nostalgia thing" in the difference between PT and OT.
I think you can argue that the OOT's f/x have aged, but that many of us who grew up on it don't see it that way because of nostalgia. So, when I say that "The OOT looks more real than any CGI crap out there!!" that's me being a nostalgic curmudgeon. I think you'd at least have a decent argument there, if that's what folks tried to argue.
However, while admittedly not the greatest drama of all time, the first two Star Wars films (ANH and ESB) still hold up as stories, even if the f/x have aged. And I think they do that a LOT better than the PT. Sure, there are some similarities in terms of the quality of each. Both have their moments of clunky dialogue. Not every performance across the board is top-notch.
But overall, I think the story of the OT and the characters of the OT are better realized and more interesting than the story and characters of the PT. I could rattle off my reasons why, but I think that the "you're looking at it through different eyes" thing, while true, only gets you so far.
As has been discussed above, adults within the industry generally applauded Star Wars. It wasn't just that it was a monumental f/x feat. It was also that it was just a solidly told cracking good adventure story. It spoke to the "childlike wonder" in plenty of adults because of how well it was done.
I don't think the PT's story, characters, etc. hold up nearly as well, though, and that there are large swaths of it that go beyond mere "childlike wonder" and in to the realm of "juvenile nonsense." And while that was present to some degree with the OT, I think it's a much higher degree in the PT.
Actually, this got me thinking about the degree to which the PT is both the victim of invidious comparison, and the beneficiary of brand name associations.
On the one hand, you can argue that the PT isn't nearly as bad as many of its detractors make it out to be. Sure it's a lousy film, but the DEGREE of hatred that people have for it stems more from invidious comparison -- it's so far below the OT that cannot help but actually look worse. Kind of like how a beat up car just standing on its own might not look quite so bad as it does when you sit it next to a pristine classic. Even one that may have had some modifications made.
On the other hand, though, I cannot help but think that many of the people who claim to love the PT really love the PT simply as "more Star Wars" rather than as films unto themselves. By this, I mean that if you stripped out the Star Wars IP from the PT, would people like it as much? Almost certainly not. If the film was titled "Fall of the Galactic Democracy", and a couple of Star Paladins ran around trying to figure out what was going on, and Anakin was renamed Albion and would later fall to become the Black Star Paladin Necrol, and Palpatine was the Star Warlock Baron Nefaar, and the hero's mentor was Kel-Dror instead of Obi-Wan, and they used monomolecular blades suspended in a magnetic containment field instead of lightsabres....people probably would just think of it as some lame Star Wars knockoff that doesn't hold a candle to the originals. Or was, "Eh, ok, but nowhere near as good as the Star Wars movies. And boy was that Vaur-Vaur guy annoying." But instead, slap on the Star Wars name, call those characters Anakin, Obi-Wan, and Palpatine, and all of a sudden you've got lead into gold. The alchemy of branding.