I agree with everyone here, Superman going, "People were going to die, of course I had to do something!" is the right way to portray Superman.
In the 60's and 70's, if you read a Superman comic, there was no doubt that Superman was a person who was always trying to do the right thing. ALWAYS. Even when he didn't
want to. Not only was there no doubt in the reader's mind, but also no doubt in the minds of any of the
other characters appearing in the comics. And that includes the minds of the villains! Sure, there was the occasional plot point where
the cover would suggest otherwise, but the story would always reveal (to the reader AND to the other characters) that, once again, Superman's devotion and sense of duty to help others are shown to be absolutely
unshakeable and utterly beyond reproach, and shame on you for thinking otherwise. He might not be infallible, but he is definitely incorruptible.
IMHO, in the trailer, what we're seeing is that he hasn't earned that reputation yet, in-universe. WE know the Legend of Superman, WE expect him to be the big, blue Boy Scout, but the populace in the movie is being introduced to him for the first time (he
is an alien, after all), so they don't know him like we do, and they have yet to have their suspicions allayed. Words are cheap, and all that, and I assume the movie will mainly be about showing Superman building that acceptance and trust...
not simply by kicking the butt of the monster-of-the-day whenever it shows up like some clichéd "hero," but through his interactions with the people around him, and the resultant word-of-mouth. And he will be exasperated that it took so long to convince everyone, but he will be happy that, finally, everyone understands.
At least, that's what I
hope this movie will be.
--Patrick