It has been five years since we have seen Frank Castle on the big screen. I believe we need a return of Punisher, and he must be in the Avengers Age of Ultron for an epic return. Why you ask? Why not? They have Scarlet Witch and Quicksilver in the movie so far. They could make it the most epic superhero movie of all time by having a ton of heroes. Think for a second...Frank Castle, Luke Cage, Dr. Strange, Ant Man, and the Avengers fighting Ultron.
Marvel has been working hard trying to come up with ideas for new movies. Rumors are flying around of a Dr. Strange cameo in Thor: The Dark World, who in the future could have his own movie. If Marvel plays their cards right, we could see a large amount of superhero cameos in the next Avengers film. It would give them the leverage they need to make those movies. Have them come in and battle Ultron. No back story, just the "call in the back up" moment where we see them come in and help fight.
If not Dr. Strange or the others, why not just the Punisher? While the Avengers are getting their ass handed to them by one of the most powerful villains of all time. Nick Fury could call in a favor of Frank Castle and ask him to come and fight. Lets face it that would be cool. If not a Punisher return we could have Fury tracking down every superhero, just listing them off and saying he can't get a hold of them. Just the mention of the names in the trailer alone would bring fans and possible movies in the future. Have Coulson talking to Fury, "Sir we have contacted all of them, Castle, the Fantastic Four, Strange, Cage, Pym, no answer....we are on our own. We only have the Avengers on this one." Fury says, "Oh do we?" That's how I would make the trailer. What do you think? Should Marvel have other heroes in the film?