Hopefully he addresses my favorite Superman theme of 'how much can Superman help the world before he hurts them through their dependency on him' theme.
I'd say save that for the sequel. They should not trust him in the first film, but win it over by the end. Then make a few years pass, Luthor is president and is pointing out that Superman is merely causing an escalation in WMD production and genetic engineering for someone to take him on.
Then comes a bad guy that is even more powerful than Superman (Earth based, please), and destroys Superman from within, and rips the planet apart by starting WWIII. Sort of like the Joker, he would put Superman in a no win scenario that would use his boy scout tendancies against him, and then the populace would turn on him when Superman couldn't save them due to the choice he's given. Something similar to Spider-Man 2 meets TDK meets Watchmen.