[quote=@Crimmy]
<Snipped quote by Guess Who>

Civil War was an entire event. This is a movie with a limited runtime.

It may not be a war, but it could be more of a metaphorical title. Besides, less heroes means less characters to balance, making the movie less crowded and ensuring that more of them can undergo development. The current cast is already pretty big, after all.
[/quote]

Let's just hope we don't get another Age of Ultron where the only thing the movie shares with the original book is the title. I still cringe whenever I think about the Black Widow and Hulk relationship in that movie.