Oh boy this is a tough one. I'm personally against it but I'll say this.
I don't think Superman has ever possessed as strong code as Batman regarding killing. Or guns for that matter, I specifically remember him loaded up when he came back from the dead in that black suit.
However this film is very much about the journey of a 'man', and exploring what that means. There are men like police officers that have to make the call to take a life maybe once or more in their life. It's almost like the Western sensibility of the film, where Clark's journey is complete [BLACKOUT]when he takes a life[/BLACKOUT]. And just like police or army who kill, it is not a long considered notion, it is mostly instinctual and reactionary. [BLACKOUT]Which is what it will be like for Superman, and he will be affected immediately by his own actions.[/BLACKOUT]