Christopher Nolan's morally ambiguous characterization comes into play with General Zod played by Michael Shannon, who was nominated for an Academy Award for Best Supporting Actor for his performance in Revolutionary Road and is also part of the HBO series Boardwalk Empire. But not necessarily with Clark Kent aka Superman who epitomizes goodness.
Superman is rebooted with this film in a more modern context. Although the Superman costume does look a little different sans the red underwear on the outside its more than just a costume. Most of all the 'S' for superman symbolizes hope and is the symbol of the house of 'El' (Superman's family). It's actually just shy of genius how David S. Goyer (the writer) has successfully melded modern mentality and the archaic design style of Superman into a cohesive thought. Everything that is has a reason and there are almost no flaws left in the plot.
Zach Snyder definitely proves that he has an innate aptitude for dealing with superheroes as real people with real problems as shown in the Watchmen. In the Man of Steel, Superman actually earns the name of SUPER - MAN. Because in the end even if you are of alien origin, its your beliefs that make you the man that you are.