Whats wrong with Motley Crue?
Nothing! I love Motley Crue, so long as Jon Corabi is singing for them...which is exactly on ONE album. I kid.
Point is, for many people, Motley Crue defined both the sound and look of "glam-metal" in the early 80's, though admittedly they borrowed a lot from New York Dolls. Pretty every band that came down the pike after that tried to look and sound at least similar to them. IIRC George Lynch even once said that Dokken made sure to use the same *hairspray* as the Crue. Either way, the Crue weren't as bad as later bands like Britney Fox, The Bulletboys, Warrant, or Poison, but they got lumped in with them and T-boned by the music media once grunge hit in the early 90's. They've managed to make a comeback because in retrospect, people didn't really hate the Crue - they just hated the whole carbon-copy glam-metal industry that they helped to spawn. Same thing with Nickelback IMO. They're not awful, I'm just sick of hearing them all the time - even when it's not them, but somebody who sounds just like them (which is all the time).
Caveat: I'm sure someone will argue that the Crue weren't the first "glam metal band" but for my money they were the most popular and most imitated of that era, and therefore symbolize to many what 80's hair metal was all about.