^ I think it's outrageous that they didn't audition any Kryptonians for the role.
Seriously though, as regards the physique, let's not forget that when Christian Bale was cast as Batman, he'd just come off The Machinist, where he was skeletal.
Speaking of which, he's apparently a little underwhelmed in his response to this casting:
http://www.scriptflags.com/2011/01/c...-superman.html