The "Avengers 3: Civil War" storyline has Marvel fanboys ablaze, but it's better not to hold your breath. For one thing, it's still not certain that the third Avengers movie will be titled 'Civil War.' While it may be a safe bet that Marvel is already planning it, we have a long way to go.

Here are some reasons as pointed out by astute reader Jean Francois in the comments section of Variety.

"The real issue here is that no superhero has a) a secret identity, b) supervillains gunning for them c) loved ones that could be in danger if this information fell into the wrong hands. If you disagree, look at the whole roster of heroes from Marvel. Tony Stark declared on TV he was Iron Man. Rhodey being War Machine was never played secretly. There is a museum(sic)wing on who is Captain America. Thor doesn't have a secret identity. Hawkeye and Black Widow are shield agents and with Cap 2 the secret is already out as are probably any other Avengers. Falcon helped Cap but is otherwise villain-less. Banner is now a loner without family or loved ones. Hell, outside of Thor and Iron Man having girlfriends everybody else in the Marvel Universe seems to be like that.

And in the end, this is why I think they can't make Civil War work on the big screen yet. They haven't setup their cards right at all." 

The article in Variety narrates the incident in the comics that ignited the Super Hero Registration Act. That has not, and cannot happen in the MCU so Marvel needs to establish that super heroes are a possible threat and that they need to be under a semblance of government control. That may be established in "Avengers: Age of Ultron" (possibly in the Hulkbuster vs. Hulk scene).

That is still Step One. The polarization of the Avengers (Team Stark vs. Team Rogers) has to happen next, but there might not be enough Avengers to polarize, even counting the twins (Quicksilver and Scarlet Witch). There are movies on the way like Doctor Strange, possibly Black Panther and Ms. Marvel to solve that. They could all be introduced before 2018.

Then there is one big reason that Avengers 3 is not yet Civil War. The Thanos-Infinity Gauntlet Story has yet to be resolved. The heroes might have to unite to save the universe before they bicker among themselves.

"Avengers 3" release date has not been officially announced but May 4, 2018 is a possibility.