It's never explained why he wants to be a hero. We got a physical Superman this time, and Snyder delivered that. What we need to see now is Superman being a boss. Cool lines like "You're a monster Zod, and I'm going to stop you."
He doesn't do that much speaking. Zod did most of the talking, fair enough, but I wish Superman could have had some more threats toward him.
If you notice in the comics, or in animated series or animated films, example, Superman: Unbound, Superman does a lot of talking when it comes to confronting the villains and Brainiac. I think it's important that Superman speaks.
While Cavill did more speaking than Routh, that was an improvement, however he still seemed to be like a quiet type.
I thought his best speech was in the scene prior to stopping the world engine. "This ship is powered by something called a phantom drive. It bends space. Zod's ship uses the same technology. If we can get the two drives to collide with another (...) So if we open up this doorway, then theoretically, they should be pulled back in. And if I don't stop the world engine over the Indian Ocean, the (what was it?) will continue to expand."
Great speech. Other than that, and the interrogation scene with Lois, sadly too short though, the following part where he speaks to Hamilton and General Swanwick."
"Let's put our cards under the table, General. You're scared of me because you can't control me. You don't. And you never will. But that doesn't mean I'm your enemy."
So before the final showdown with Zod, Zod gives his famous speech, Superman is pretty silent. Even during the mid-battle, Zod says, "There's only one way this ends Kal. Either you die or I do."
The only boss-speech that Routh gave in Superman Returns were just "I see an old man's sick joke...You have something that belongs to me." That was it, that along with a physical Superman was missing.
Reeve had more dialogue than Routh or Cavill.
I mean if they would write such scenes such as in Justice League Unlimited, the final episode.
Superman is at his best, not only physically owning Darkseid, but speechwise.
"That man won't quit as long he can still draw a breath. None of my teammates will. Me? I've got a different problem."
"I feel like I've been made in a world full of cardboard. Always taking constant care not to break someone. To break someone! Never allowing myself to lose control. Even for a moment. Someone...could die. But you can't take it, can't you big man? What we have here is a rare opportunity for me to cut loose, and show you just how powerful I really am..."
That was pure awesomeness. Confronting the villain in a boss way. It's relevant, shows Superman is human and cool. Even people who aren't fans of Superman can relate to Superman in that scene. Another thing is the self confidence. I want to hear Superman speaking more to the villains.
Anything that would work such as "Don't do that or I will..." or something along the lines of the comics or animated media incarnations.
Also from Batman-Superman: Public Enemies, one of his most human moments while punching Mongul, "I'M SICK! *PUNCH*...OF LEX-LUTHOR! *PUNCH*"