Brando is considered one of the best American actors of the 20th century and is credited with changing the actual approach to acting, giving the Britons a stroke. (I know he learned from the "method" people, but he had the most lasting effect of them all.)
Anyway, could he have done so if he was not as handsome as he was? If he had everything else, even the physicality, but he had a less-than-appealing face, would someone else have taken the throne?