Consider this: Iron Man has been appearing in Marvel Cinematic Universe movies ever since 2008, and he's essentially considered to be the flagship character of the entire franchise - the one that brings audiences back into theatres time and time again. Now, there's going to be a film which will set out to create two opposing sides, with Iron Man leading one such faction. But has anyone actually stopped to consider how a Civil War might affect an established character with the weight of Iron Man? That it could potentially undo years of characterisation and development? Because Marvel are going to have to essentially make Tony Stark into something of an antagonist if the movie is going to work; not exactly a full-on "bad guy," but somebody who Captain America - assumedly poised as the "good guy" protagonist, given that this is still (above all) a Captain America flick - has to oppose in order for there to be any drama. And Marvel can't just dance around the fact that the Cap and Iron Man are going to lead different teams; there needs to be a genuine conflict of interest and not a petty squabble. If it's handled wrong, Tony Stark could come off looking like an assh*le - not in that charismatic, Robert Downey Jr. way, but for real. It's inherently dangerous ground to walk.