I think the Challenger is an inspired update of an old design. Ford also has done a consistently great job with the Mustang (until the electric suppository they call a Mustang E...)
I have been a fan of GM, but they must have sent all their designers to a gulag sometime around 1980. Aside from the Corvette and Camaro, the styling of their passenger vehicles was freakin' awful, and the interiors weren't any better. When Olds went under, if I were CEO I would have scrapped all the styling on the Chevy cars and used the Olds bodies instead; they had a few attractive points. But in general, it all sucked. For about three decades there wasn't a single GM car I liked other than the 'Vette or Camaro.
For the resurrected Camaro - my thought for the design would have been to park a 1968 Camaro in a big garage, put chairs around it, send in the designers and tell them "don't come out of the room until you have a design that echoes this car." They came within shouting distance of it, but I thought it was not as close as the Challenger or Mustang.