also superman has the problem that he's a bit boring due to being unbeatably 'super'. a little personal anguish might add some interest.
As long as it doesn't change who and what Superman is, then fine. If it serves the story, then fine. But if it just "dark for the sake of dark", which is what alot of TV and movies have been for the last decade, then it's silly.
But, I'll reserve judgement on MAN OF STEEL until I actually see it.
I am tired of the argument that Superman is so powerful. The intrigue of his character is his personal pathos. He has lost two sets of parents and his entire birth world--he is the ultimate immigrant wanting to fit into society but also maintain his heritage. What's more, despite everything that has been thrown at him in life, everything that has been taken away from him, he remains positive and optimistic about the world.
How do you write a story about Superman? Tempt him. Tempt him with returning to his people. Tempt him to give in to his power for the "betterment" of the world. Tempt him with true happiness, truly "fitting in" and finding his place in the world.
Superman's trials are not physical, they are emotional and mental.