I liked the Kevin Smith script when it came to that. No origin story. Just Superman from the start.
I would have liked a movie that started off in that vein. I've used this analogy before, but to use it again, I'd have taken the Goldeneye route, not the Casino Royale one.
But look at it from a Hollywood perspective. Batman Begins, Casino Royale - reboots from the start of succesful franchises, leading to new successful franchises. Superman Returns - not so much. Continuation that underperformed. That's why we're getting a reboot of Superman and a new origin story.
As someone else pointed out, Spider-man is being re-booted, with a new telling of an origin story last seen on the big screen less than a decade ago, as opposed to Superman's 30-something origin movie. So this is hardly an unreasonable way to relaunch The Man Of Steel.