>I refuse to believe
>there isn't a writer who can't find a way for Supes to get out
>of that situation without killing Zod.

I think you're ignoring the fact that it was a concious choice to go in that direction. It wasn't done because they had no other options and were left in a panic or something. They deliberately chose that direction because grandpappy's boyscout iteration of Superman is honestly not going to cut it anymore. Those same writers could have easily taken a different path and simply chose not to.

This notion that "Superman shouldn't/doesn't kill!" is antiquated. The "pretty family" being in harms way showed a man who was more concerned with protecting innocent people who were about to be murdered than saving the life of the murderer. These weren't people who might die incidentally as collateral damage in a fight he had no experience to draw from in order to keep people safe, it was a family about to be intentionally murdered, and Superman made the right call.

TWS is so far removed from this scenario it really shouldn't even be mentioned.

Bucky wasn't hellbent on destroying the world or murdering innocent people. He was a brainwashed assasin doing essentially the same kind of work Cap was, albeit for a different side and with less honor. Bucky tried to kill his targets, but his targets weren't innocent people. They were specific, direct enemies of the people who brainwashed him.

Further, Bucky was hurt and presented no imminent danger to anyone at the time Cap saved him. Cap wasn't faced with anything approaching the same choice Kal-El was, and if you put that same pretty family in front of Bucky with Bucky's finger halfway through a trigger pull, Steve just might make the same call.

Bucky and Steve had a unique bond and past history together and Bucky was an innocent pawn in a game he barely knew he was playing, was no immediate danger to anyone, and Bucky had shown glimpes of recognition that Steve picked up on. This is a pretty far cry from Kal-El's predicament.