1. Frank Castle: Agent of S.H.I.E.L.D?
Following the events of the Avengers movie the world was a much different place. According to Marvel canon the world is aware of the existence of Superheroes and we've finally reached a place in the evolution of comic book movies that resembles the current universe contained within the pages of each weekly issue. With New York being the focal point of the big end of movie battle wouldn't it be rather fitting to bring Frank Castle into the Agents of S.H.I.E.L.D TV series even in a recurring guest role to help keep his city safe from future attacks? Sure Castle isn't a Superhuman but we're pretty sure S.H.I.E.L.D wouldn't care if he was useful to them and even if he wasn't he could show up from time to time to screw with Coulson and company seeing himself as the true protector of America's finest city. Castle has a strong moral code but yet he still comes into conflict with the rest of the Marvel heroes which would make him an interesting foe acting against S.H.I.E.L.D but striving for the same result. This could then lead to a cameo in a future Avengers movie or a spin off of his own but given the popularity of Marvel's long awaited TV series it's a safe bet that this would be the perfect way to bring Frank Castle's Punisher back for a whole new era and a new, family friendly generation.