Fans are still split on the destruction of Metropolis in Man of Steel, with defenders of the movie often overlooking the true complaint about the probable mass death in the movie, which isn't that Superman couldn't save everyone, it's that he didn't try.
The same thing seems to be overlooked by Snyder and Goyer as well, in a recent interview, Snyder talked a bit about the mass death in the movie:
I wanted the movie to have a mythological feeling. In ancient mythology, mass deaths are used to symbolize disasters. In other countries like Greece and Japan, myths were recounted through the generations, partly to answer unanswerable questions about death and violence. In America, we don’t have that legacy of ancient mythology. Superman is probably the closest we get. It’s a way of recounting the myth.
This is a bit different from Goyer's feelings about the destruction, telling Bleeding Cool in an interview:
...I think people die [in Metropolis]. Clearly hundreds if not thousands of people have died while the gravity machines are going off. There were probably even people who died in Smallville.
When you’re dealing with a threat like this, there will be collateral damage...
Again, most of the fans that had a problem with Man of Steel didn't complain about the fact there were casualties or deaths from god-like beings fighting in a big city, they didn't complain that the hero couldn't save everyone, they complained that he didn't try. Even in Smallville, he flew the super-powered bad-guys into town to do battle, endangering more lives. Not only is his apathy about the death not very "Superman"-like, but it makes the decision at the end mean that much less and makes making out with Lois in the middle of thousands of dead that much creepier.
I think it's much more a case of creators thinking that destruction looks cool than thinking about what makes sense. Consider the recent Injustice game: 'good' Superman has to shoot car-fulls of people with his heat vision as a bad guy snatches them off the road and throws them at him. It certainly seems the people behind these games, movies, and comics aren't thinking too deeply about the action.
That's my two cents anyhow, but at least Snyder's words above offer you a look at what he was going for with his approach.