Apparently a deleted scene for the film would have made Superman seem more darker as a character since it would imply he's very selective on who gets saved from danger and he needs to be in the mood to do so.
Zack Synder tried to imply Superman would probably be dealing with mental breakdowns if he was always in a life saving mood.
http://www.joblo.com/movie-news/zack...g-too-dark-760