Civil War was, at the time, a revolutionary idea in the comics. Having basically all the superheroes in the universe pick a side over a highly controversial issue, then fight it out to try and make the other side come to theirs.
With it’s movie adaptation, it’s a clearly different animal. As the MCU only has a fraction of the characters that were in the comics story, among other things. This has not gone unnoticed by both the fans, and the writers. Who told ComicBook.Com they knew that there would be major differences.
“We did the same thing with Winter Soldier,” Stephen McFeely says. “If you went into Winter Soldier thinking you were getting an exact Brubaker, Red Skull, cosmic cube, and then the Russian’s head, you weren’t gonna get that but you were gonna get a lot of the character stuff out of it. Same thing here. We have to honor the thirteen movies and in that universe we’re not necessarily honoring the 200 characters on the splash page universe.”
“We’re also, as everyone knows since this was announced, there are virtually no secret identities in the MCU so we can’t do the whole unmasking plot,” Christopher Markus chimed in. “We don’t have 200 super heroes to have a fight with so this has to come from a character issue as opposed to this, ‘We want to take off your mask’ thing.”
Despite these changes, early reviews of Captain America: Civil War are very positive, and the changes to the story seem to be irrelevant. You can make your opinion known when the film comes out May 6th.