2. Death
Lets be honest: one of the great shortfalls of comic book storytelling, especially in the modern age, is the tendency to make our heroes (and their friends, allies, and anyone integral to the plot) untouchable. If anyone does die, theres always a way to bring them back, without threat of consequences in many cases. The Marvel Cinematic Universe has already continued that trend with the death of Phil Coulson in the Avengers and his return in the S.H.I.E.L.D. television show. Mind you, Im not upset about that I love Phil Coulson as much as the next guy, and I have faith that Kevin Feige and the other folks over at Marvel Studios wouldnt be bringing him back for no reason. But Thor: The Dark World gives them a chance to do something else entirely. Its already been made clear through the official synopsis and the trailer that Thor will be asked to make a great sacrifice of some type, and its pretty easy to infer that that sacrifice will probably be the life of someone close to him. There are plenty of candidates for this sacrifice Jane Foster, Sif or one of the Warriors Three, or even Thors parents or brother. Whatever the case may be, the real challenge is making the sacrifice both a necessary and worthy one in the eyes of us, the audience not to mention making sure it sticks.