It's so hard to reinvent music but I think Axl and GNR as a whole did a great job. When they first released AFD it was what I thought a different and refreshing sound compared to what was out at the time.
I dont think Gn'R really reinvented music with Appetite, nor do I think that was their goal..but I certianly agree that it was highly refreshing compared to all the Glam Rock shit that rock was dominated by for the longest time..
Gn'R took influences from their heros like Aeromith and the Stones and upped the bar with Appetite and that album was just like "Wow..there's nothing out there like this now..." and there really wasn't for the most part..and the appeal of bands like Poison or Warrant went to that of stale cheese and finally rock was back again...ala Gn'R, Skid Row, Motley...