To Me I think Max Landis Director of the movie Chronicle has a point here when it comes to how to portray the man of steel.
So this is what I think would make a better movie, step one: start with the man of steel already wearing the suit. If we tell the origin, it should be a small flashback while he is explaining it to Lois, we all know Superman's origin, this isn't Hellboy,Psylock or Invincible, we are talking about the story everyone knows. As for the villain, I would go with Brainiac.
a lot has been written about the aborted movie disaster that was superman lives and that we dodged a serious bullet in it not being released. Yet how many times must we retread Luthor, or Zod. I think the use of Zod in man of steel (despite Michael Shannon being a hell of an actor and doing a great job in the film) is that it smacks too much of having to retread over the most successful film of the previous franchise (Same with the plot of Star Trek 2 which had to be recycled twice!)
Now for the coup de grace. For an endgame Brainiac unleashes an army of drones onto the city of Metropolis, and explains that while you may have thwarted my plans, I will have the last laugh, for all your powers you cannot be everywhere at once, you cannot save them all and you will spend every last ounce of strength trying, you will tire, you will weaken, and you will die. Cut to superman trying in vain to do just that stop the drones save the city, spotting a schoolbus about to go over the bridge into the river he flies trying to reach it in time only to see the bus stop, it's fall halted by a golden tether, Pan up to Wonder Woman holding the other end, and yelling "Don't just stand there, grab the other end!" When he asks who she is she says she is like him, and the rest of us are here, we are here because you inspired us, and we are here to help. Cut to The flash racing past drones knocking them over and picking up a kid who is about to be hit by a runaway truck, Cut to the Batwing blasting arial drones over the river, and Green Lantern holding up a building with his power ring. This is how we introduce the Justice League as a big reveal at the end of the movie, not some cryptic post credits vignette of Amanda Waller trying to talk Clark into joining her JL project. In fact for fun, I would place Ambush bug as the post credit vignette urging movie goers not to reveal the secret twist ending and possibly throwing out some real tidbits about the JLA movie.
Well that's my $0.02, for what it's worth.