I'd love a sequel, but I'd love even more to see a prequel! I don't know if it's just me, but I really loved the stuff on Krypton. I'd watch a movie about Jor-El.
It's true that without Clark we missed the "secret" aspect of superman. The Superman of this movie wasn't much about secrecy. As he grew up he all but openly used his powers. It's a wonder no one tracked him down before.
It's strange also that they had Lois know his secret already. It's is usually one of the main aspect of the CK/Lois relationship. We'll see how it goes in the next movie.
That said I think it's the best Superman movie in years and I really loved it.