Sorry, what I meant to imply was that I don't want to see any origin story at all. That's been done to death with Superman. We don't need to see it again. I don't necessarily feel that a reboot HAS to include an origin story, and I don't think another origin story would help this franchise.
I'm trying to think not just of the next Superman movie, but the next 2-3 Superman movies. That's how the studios do it these days, and I guarantee that WB is trying to develop this franchise into at least a trilogy. You're right that they could make people care about Superman and kill him off in the same movie. But I still think the Doomsday story would have more emotional impact near the end of a successful franchise than at the beginning. If you kill him in the first film, where will the suspense be in the sequels? What villain can top the villain that killed Superman? It also may be a bit cheesy to have Superman die in the first film, and miraculously come back 2-3 years later for a sequel. It may work in comic books, but it won't play as well with the general movie going audience.