It's a valid point about Axl's hair only being like that in the first video, but they pretty much always looked to me like they were outfitted by a corporate marketing department.
I wasn't entirely grouping them with the other hair/makeup bands of that era, and I do think they were a cut above those bands. Paradise City was great, notwithstanding the "where the grass is green and the girls are pretty" God-awful lyric. They weren't as good as "classic" Aerosmith, but as good as Aerosmith has been late-80's and thereafter. Also, the other hair bands didn't seem to carry the pretentions of GNR. Poison and Warrant, for example, were just stupid party bands. GNR were better than them, but if Aerosmith was a poor man's Led Zeppelin, then GNR was a poor man's combination of Aerosmith and Led Zeppelin.
The reference to Metallica is a good one, because they're a band that I think had some influence. They pretty much popularized speed metal through Kill 'Em All and Ride the Lightning. By the time GNR came around they were getting overblown and may have been influenced by GNR in that regard. Nirvana may have had some predecessors in what they were doing, but GNR wasn't exactly breaking new ground either.
I'm not sure I buy that Kurt was super image conscious and would deny liking something and Axl was just baring his soul come what may. Kurt was definitely into being "punk," apparently to the extent of insisting that they physically carry their equipment around, to Courtney Love's annoyance. Axl's apparent desire to be like Queen and Elton John may explain why he got so overblown, but he also gave every indication he was into that "megastar" image, which isn't exactly punk. (I'm not saying being "punk" is necessarily something to which to aspire, because it's often not.) I don't think it was about "denying" he was a celebrity, but I think Axl embraced and sought the celebrity and Kurt didn't. As an analogy, Matt Damon said that he had always wanted to be an actor, whereas his friend Ben Affleck always wanted to be a movie star. In this situation (and no other), Kurt would be Matt Damon and Axl would be Ben Affleck. In short, I think Kurt was about the music and Axl was about the grandeur.
I don't know who popularized what in terms of punk, but we may be using different definitions of that term. I wouldn't consider Aerosmith's Live Bootleg to be punk at all. It's just good old blues-oriented rock & roll, and one of my all-time favorite records. I don't think it's punk, though. When I think of punk/rock mixes I usually think of Nirvana and old Iron Maiden. I don't think of stadium rock with long guitar solos.
Oh, and don't say bad things about Boston.