Looks like the Man of Steel can of worms is being re-opened by writer David Goyer.

He seems to think that Superman should be allowed to kill.

This is one area, and I've written comic books as well and this is where I disagree with some of my fellow comic book writers - 'Superman doesn't kill'. It's a rule that exists outside of the narrative and I just don't believe in rules like that. I believe when you're writing film or television, you can't rely on a crutch or rule that exists outside of the narrative of the film.