Call me cynical and part of the wrong audience, but the [Captain America: Civil War](tag:994409) ending isn't going to be controversial. To me, the word "controversial" is meant more as part of the marketing strategy and the legitimacy of this comes from how huge an impact the Winter Soldier ending became.
[Important to Note: Spoilers from the Civil War comic and potentially the film.]
If there was really going to be a controversy, it'd be the death of Captain America as per the comics. There's just one problem here: Contracts. Chris Evans is set up to be in both halves of Infinity War, to the best of my knowledge. So, unless the Russo Brothers intend to skimp that whole part of the contract with a deus ex machina of using the Time Stone to revive all of the fallen heroes, this won't happen. No, the real controversy here will be that Civil War had a massively misleading yet viral marketing campaign. However, that's a different story and my thoughts on that can be found here (link to be added later).
Obviously, Civil War has a huge amount of intricacies over the 98 issue event along with the events it spawned afterwards (The Initiative, the Secret Invasion*, etc.). Instead, we're looking at a 150ish minute film which is not nearly enough time to cover every aspect of the event. So, I will respond accordingly with how I feel the three acts of this film will work:
Act I: The Foundation
The trailers have hinted at Bucky becoming "Public Enemy Number One" of sorts and the event is something similar to 9/11. I am in no way trying to say that 9/11 is by any means a demeaning event nor am I trying to offend people. I am simply saying that the sight of an airplane plowing through a large building is most likely meant to bring in comparisons to the event including repercussions such as UN involvement in Southwest Asia. This is also a Captain America film, so naturally anything that hits home for Americans will be far more effective. That and it's important to consider the comic book they've adapted it from:
In the original Civil War story, some rookie heroes (much like Bucky given his criminal history) accidentally cause an explosion in Stamford, Connecticut, that leads to the death of thousands including a school full of children. After the recent rise in school shootings, most notably Sandy Hooke, this is not the best scenario to enact the Sokovia Accords. The tragedy really adds an emotional factor to the comics that will be missing which is a shame, but a reasonable precaution.
Anyway, this event forces the government to push the heads of the Avengers, Captain America and Iron Man, to sign on to the Sokovia Accords. Iron Man, feeling responsible for the events in Sokovia, signs on whereas Captain America feels it's a violation of his basic rights as a human and a citizen. His refusal further deepens the rivalry that Marvel has been establishing since Avengers (2012). This also most likely leads to Captain America taking what remains of his New Avengers and forming his "Secret Avengers" faction. Though, they're not so secret given the teams are about even in size and being a super hero isn't illegal.
Act II: The War
Like I said, the teams are going to be extremely small compared to the comics. There are a lot of factors behind this including a lack of characters in the MCU, an insane budget boost needed to add characters, and the film isn't nearly long enough to adequately support the battles involved. General Ross is in the film, so there's a rumor going around that he may become Red Hulk. I'm also convinced that War Machine gets killed during one of the battles. Both of these events would make sense in order to replace the following:
The creation of Red Hulk defeats the need for Iron Man to create a Thor clone (Ragnarok). There's also the possibility that Red Hulk goes rogue much like "Thor" had and killing someone. In this case, War Machine instead of Goliath unless Hank Pym takes on the name Goliath and gets killed in the film (unlikely).
Black Panther will definitely take note of these events, especially the desperate measure taken by Iron Man in his attempts to win the war at all costs. His breaking point will most likely be the unnecessary invasion of Wakanda. T'Challa will most likely stress that his country intends to remain neutral in regards to American politics and this blatant disregard for his country's wishes will most likely push him to Captain America's side.
Act III: The Resolution
Seemingly out of nowhere, this guy comes out of the shadows to give the heroes a reason to unite against a common cause. He'll probably be leading Hydra which will have its repercussions on Agents of S.H.I.E.L.D. afterwards. Then, instead of a natural progression of violence, death, and chaos, we get a deus ex machina of "You need to take on the larger threat." We're sacrificing the maturity Captain America expresses in the event in favor of a reminder that these people are meant to be a united team and Infinity War still needs to be set up. I assume somewhere amongst the chaos stirred by the "unexpected" (for the majority of the audience at least) of Zemo, Crossbones will step out of the shadows to take a turn at punching Captain America as revenge for Winter Soldier. Zemo will be defeated, the Sokovia Accords will remain intact, all will be right in the world for the next 2 years. What we won't see:
Captain America stands trial for his involvement in the war, he gets assassinated by Crossbones and a brainwashed Agent 13, and for 5 issues, Iron Man and several other members of the Marvel Universe cope with the repercussions of his death. Again, too much of an emotional impact to truly capture in a 150 minute film.
Then again, I could just be dead wrong and none of this is even close to how it ends. In which case, I will post a retraction. I may even post a retraction following the next trailer depending on how much they reveal.
Also, take a minute to check out this article on Zemo's real identity. I definitely enjoyed the theory and if he's right, we're looking at a real controversy on our hands!
*As part of an article I wrote a few months ago, I mentioned how the Secret Invasion could fit into the MCU. If you're interested, you can find that here.