AMC had a difficult time competing with the mainstream. They had a few respectable vehicles, i.e. Rebel (Machine), AMX ... I believe Breedlove, Penske and Mark Donohue made them more popular.
As for the Gremlin, it was certainly ahead of the Ford Pinto... I never seen one blow up after a rear impact. In terms of being ahead of its time, well in my opinion all vehicles built today are all a reflection of innovative thinkers from the past.
I love AMC only because I enjoy automotive history. If you follow the roots of these now dissolved brands, in some shape or form, I believe you will find a hint of their legacy still in production.
I think its a stretch to believe AMC was in the forefront. I guess it's safer to say they built something unique at a time that didn't fit the mass market. Not that they would have done any better if the market was ready, mainly because they weren't seen in the same light as Ford, GM or Chrysler.