The only things I think a sequel needs are a bigger dose of humor, and a more charismatic villain.
we're going to see more of Metropolis and Lois and Clark, since that's where the first movie ended up. And I'd be surprised as hell if we didn't see the businessman Lex. So I don't think there's any real need to pinpoint those things.
I'd love to throw in Supergirl and Bizarro too, since I'm a big fan of those characters, but that's more a wishlist than something I think the sequel really needs.