Hancock was originally a screenplay for a film called "Tonight He Comes". The story revolving around a darker superhero who when he climaxed killed whomever he was with. A story of sexual frustration, super powers and some genuine dark thoughts crossing what is good and evil. This got picked up by the studio's, reworked so they could actually make a movie that would appeal to a mass audience, and we find a dumbed down version of an original screenplay.
Not to say that the creative side didn't leave hints of its true origin though, yet financial constraints and wants just have to dictate the content of a blockbuster film in this business.
On Kung Fu Panda, it was genuinely funny with some pretty bloody good fight scenes though the first five minutes is probably the best bit of the movie. The Panda's dream is just so awesome you could go blind.