So we'll have to see the movie but I was slightly worried about Lex going to jail so soon. While that doesn't mean they won't use Lex in the future, it may just mean that the world will already not be able to trust Lex Luthor. I would want the antagonism between Superman and Lex Luthor to keep on going for a while.
I think one of the reasons that makes Lex a great villain is that he's intelligent and a genius and highly unstoppable, which makes Superman vulnerable. Superman and a few others (just Lois to name one) know the truth while the rest of the world brands Lex Luthor a hero.
Superman can't really stop Lex Luthor or expose him. One of the things that makes Luthor awesome is that he manages to gain the citizens of Metropolis' trust for a long time, once he escapes from jail or gets out, he tries to convince the world and Superman that he's a changed man, and runs for president, and tries to frame Superman for a huge crime he did not do...then Luthor evolves and gets worse, and no one can trust him again...
Would Lex really be considered that smart, or that great of a villain, in the end if he just goes to prison by the end of the film?