Did anyone else think the Klingon scene felt unnecessary? They were only there because Trek needs its aliens, and maybe because there needed to be another action scene. On that last point we could have figured out Khan was badass later on without it.
Have Kirk show up with a phaser pointed at the back of Khan's head and it would have changed nothing.
I think they added a Klingon scene to set up a potential conflict for a third film, if there is going to be one.