5. Clark Kent
At its core, Man of Steel was a story all about Kal-El, exploring the how and why behind his decision to become Superman and protect the people of Earth. The "bumbling unassuming journalist" Clark Kent persona was not featured until the very last scene in the movie; setting the stage for future installments. An obvious story thread for the followup to dive into is showing Clark Kent in full force. Now that Kal-El has chosen to live amongst the humans, the filmmakers can explore how Clark interacts and fits in to our society. This would also be a great opportunity to introduce Jimmy Olsen - a character missing from Man of Steel - and have him be a friend of Clark's in the sequels. I can understand why Snyder and Goyer did not focus on Clark and the Daily Planet at all in the first film. There was so much ground to cover and Kal-El's identity crisis was the major crux of the narrative. It would have been extremely difficult to balance the two personalities out and now that I've seen the film, I can't really see where it would fit. Now that Kal is no longer the outsider, jumping from odd job to odd job, it would be ideal to show Clark in the next film.