Just remember, if the superbird or Daytona was never made and 50 yrs later someone made "the car Mopar should have made to win NASCAR", I'd venture to say folks would have laughed at the attempt.
I don't think it looks bad when you compare it to 4 door versions of other cars like a 70 b bodies. The rear roof line is actually pretty similar, so I'd think you would have seen some consistency across the different models.