I'm going to start this article with a question. What makes the styling of a 1959 Cadillac stand out so much? Is it the enormous fins? The yacht like proportions? The ridiculously over the top use of chrome? Or is it something else entirely?
I think what makes it stand out so much is that it perfectly represents the era that it was produced in. In the 50's, people were into space age stuff, hence the giant "stabilizing" fins and "afterburner" tail lights. I don't think that the fins in particular made it great (although they sure are iconic) but it's what the fins represented. The forward looking, happy era that people recall when they see those fins is why they love it.
This brings me to the subject of "retro" styling. I see retro as a car company trying to capitalize on the happy emotion that people feel (conscious or unconscious) when they see a car from a particular era. For example, Chevy hopes that since the '69 Camaro is such a classic, they just have to modernize it to make another classic. I don't think that works. People love the '69 Camaro because it is so representative of its time. Today's world is very different than 1969, and the same influences from 1969 don't necessarily make sense today.
That's not to say that looking back is a bad thing. If Ford looks back at the Mustang and says, "hey, we made a youthful, powerful, stylish coupe and it sold well!" then good for them. If they look back and say, "we made a coupe with 3 taillight bars, grille lights, and window louvers, and it sold great!" then I think they're missing the point. It becomes retro. The Mustang was great because it made sense for 1964 1/2.
The point of all my rambling is to say that copying the past doesn't make another classic. Designing the best car you can, reflective of the time it's designed in, makes a future classic.
Does this make sense, or am I a raving lunatic? Let me know!