From what I understand it wasn't just a modern thing, but more or less the situation that happened to the first two films of the PT but earlier. Where the younger generation on the whole liked it, but the older audience was polarized by it. I'm pretty sure it was not considered a classic near the caliber of the first two until the Special Edition theatrical re-release. Though there is still a stigma on it for many. While I think it is one of the three weaker Star Wars films (yes I like one PT films more than an OT film, on the whole I think SITH is better) I certainly do not think it is a bad movie.