I hope he's presented with a similar situation in a future movie. Maybe Lois is the one in harms way?
The way they (meaning Snyder and Goyer) resolved the issue of Superman killing was to do things in reverse: normally one would look at the situation as "Ok, this guy has a secret identity like most every other superhero that comics have brought to our attention and imaginations, and what is the universal version of "Kryptonite" for all superheroes, period:
Humanity, meaning the ultimate weakness for any superhero is protecting human lives. In spite of that, and in spite of having powers that normal people just can't comprehend, those powers are rendered basically inert and non-functional whenever a human life is put into harm's way directly
as a means of control over said superhero or to be more specific:
"I've got <insert name of loved one or friend or coworker or whatever here>, if you don't do what I'm telling you to do I'm going to kill <whoever>..."
A superhero's top internal priority is protecting their secret identity (assuming they have one, i.e. Tony Stark outed himself to the world as Iron Man so he's not an example for the most part and in fact it makes him and his loved ones even bigger targets as shown in IM3, go figure) so that the people they care about the most or even love don't become targets for the bad guys to be potentially used as leverage against said superhero.
For MoS, instead of putting Kal on the spot and having Zod holding her up by the neck (more or less) and threatening to kill her if he doesn't surrender is, Snyder and Goyer looked at it somewhat like this:
a) it's been done before (literally in Superman II)
b) everyone is expecting such a situation
because it's been done before so why not do it again (that makes sense, right?)
c)
because it's been done before (literally) and
because people are expecting it, it's time to shatter those expectations
and that's what they did. Instead of putting the focus on one person, Lois, they put the focus more on several people at one time; even better they chose a family (at least we assume it's a Father, Mother, Daughter, and Son as shown in the movie with 4 people) and Kal kills to show he's protecting
us and not just one person.
Least that's how I understand it.