Well, you must pay more attention to men's bodies than I do, because I never noticed the difference in physique. If anything, I was surprised to learn that Cain was a former football player, because he never struck me as particularly muscular or burly. He always seemed to me like a fairly "soft" Superman, befitting the show's romantic-comedy approach.
And I'm surprised by your rather aggressive negativity toward Reeve. Now, for a long time, I'd soured on the Reeve movies (until my recent reappraisal of Richard Donner's work with the character
), but I always felt Reeve embodied Superman, looked like Superman, better than anyone else. Yes, there are differences in his facial structure, but there's more to a face than its structure. A face is a dynamic, expressive thing. And the expression, the attitude on the face of Reeve's Superman -- the combination of utter confidence and strength with easy gentleness and boyish openness, so that you recognized his power and authority yet trusted utterly that he was a protector rather than a threat -- that is what Superman should be, regardless of the shape of his nose or the circumference of his chest.