I had a nightwatch blue 1982 Mirada, and it hadn't got to the point where the paint had been sunburned off, but the horizontal surfaces were much lighter in color than the vertical surfaces. It is a terrific color, not in your face like some of today's blues on Mustangs, Camaros and Corvettes. However, it is not dark enough to make body lines fade.
My 1980 Cordoba Crown is Light Heather Grey Metallic, sort of silver metallic in color (to use the non-marketing colour description_It is as bad as the blue Imperial, if not slightly worse.
I have not come anywhere near the point where I am going to have the Cordoba repainted (original color), but when I do, i will have some serious thinking to do about whether I repaint it using the factory single stage acrylic enamel, or go to two stage base coat/clear coat. The single stage is factory issue, but the two stage has better shine and will probably stand up to the environment better.