I don't really think it was nostalgia. Had these movies had been just as good as the originals (or near it) I don't think they would have been scorned much. Case in point: Beavis & Butthead. For many people, that was a nostalgic franchise. Maybe not from their childhoods necessarily, but still nostalgic. When they brought that back recently, critics adored it. It was as if the show had never left. The concept was slightly updated to accomodate modern times, but it still felt true to the episodes from the 90's. Personally, I've yet to hear anyone cry "nostalgia goggles" on this, because people think it's good.
If it could work for an old cartoon about two 90's era teenagers, it could sure as hell work for one of the most beloved film sagas of all time. So why didn't it? Well...because they weren't very good. I do agree with Moviebob though, they're not horrendous movies, they're just meh. If these movies hadn't been affiliated with Star Wars, they probably would have just been your typical summer blockbuster. The type of movies that makes a pretty good chunk of money at the box office, but everyone forgets existed a few years later.
And I think the prequels really could have worked. The concept is fine, and if you just take the main plot points and put them in an outline, it doesn't sound bad at all. Take a look:
- Small slave boy with dreams is taken into Jedi Order
- Boy grows up, but his mother is killed and he falls into a forbidden love
- Meanwhile, a Separatist army being manipulated by Palpatine is warring with the Republic.
- During war, the boy gives in to his anger out of fear of losing his wife. Leads to his downfall and birth of the Empire.
Really, this sounds FINE on paper. The problem was all in the execution. The character is written so haphazardly that he's impossible to like. As a kid, he's way too pure and innocent as well as played by a terrible child actor, and he grows up to be a whiny, self-absorbed, borderline psychotic man child that it isn't tragic at all when he officially turns to the dark side. And even THAT feels forced. One second he's all "I must stop the Sith and save my wife" and the next he's all "I'm going to kill children and the Jedi are evil because Palpatine told me they are." There's little to no actual development here, the character simply changes at the convenience of the plot.
And Anakin isn't the only problem. Palpatine's plan is way too complex and convoluted, the movies are filled with boring political debate scenes that put adults and children alike into comas, certain side-characters are really annoying and just there to sell toys, they create plot holes in the original trilogy (Leia remembers her mother, huh?), they create plot holes within themselves, and-most importantly- they just aren't very interesting or engaging. I love me some good lightsaber action too, but these movies fail plot-wise.