Superman’s job is to fight for and inspire those who cannot fight for themselves. His job is to make this world a better place and to help all men realize their potential as supermen. Further to this, it’s important to keep in mind the Superman/Christ parallels WITHOUT being obvious and heavy-handed about them. Superman has to think differently from us, and when we see into his head, we should be shocked by the clarity and simplicity of his brilliance and compassion. This is a god sent to Earth not to suffer and die but to live and inspire and change the face of the galaxy by his deeds and reputation.
More on what Timothy Callahan, writer of "Grant Morrison: The Early Years", calls "the essence of Morrison's Superman" and how the recently completed All-Star Superman fits in with Morrison's attempts to reboot Superman in 2000 at Comic Book Resources.