I would change one thing with the order of the movie though, I feel like it would have made more sense if:
So here's my thought, in the most spoiler-free version I can produce.
We think of "Team Iron Man" and "Team Cap" as representing two sides of a specific issue, specifically oversight. Stark agrees to sign on to the Sokovia Accords which mandate that a special UN committee would have jurisdiction over deciding if and when the Avengers would be allowed to act. Rogers doesn't. So Team Tony is in favor of oversight and Team Rogers is not in favor. But I think there's a different duality going on besides this one. If Thanos were to show up and threaten to destroy the Earth, how many people think Tony and Rhodes and the Vision would sit at home and wait for a committee to authorize them to save the world? Yeah, me neither. I think if the stakes were high enough and the threat big enough *all* of the Avengers would act, and I think they all know that. I think even Ross knows that. So why don't they all sign?
Tony signs for a lot of complex reasons having to do with where he is in his life at this moment in time, but I think one reason he signs is because he knows the Accords are a compromise, and in a real emergency if he had to he would violate them. He signs knowing he would act anyway if he felt it necessary. And that's something
Rogers cannot do. Tony can sign with a clear conscience (as clear as his conscience ever gets) because he thinks signing is a means to an end. It is just a squiggle on a page. Rogers cannot sign because he *knows* he doesn't believe in the Accords. He knows he will break them if he thinks it is necessary. And because he knows he will break them, he can't sign.
Team Tony isn't just about oversight. Team Tony believes you have to do what is necessary. Think about who is on Team Tony (no secret given the marketing). Stark, obviously. Rhodes - Tony's friend but also a soldier. The Vision. Romanov. I think it is obvious that all these people can be safely characterized as being people who will do what is necessary when they feel it is necessary. They have situational morality. It is not a big extrapolation to see the Vision, an artificial intelligence, as having a similar governing principle: if it needs to be done, the Vision will do it. That's just logical.
Team Cap is anchored by Steve Rogers. He will do what is necessary but he's a man of principle. He doesn't like to compromise for the short term expediency. He tries to act towards higher principles, even if they have short-term negatives. He believes what's right is always right. He doesn't believe in necessary evils. Even as a soldier he chafes at doing the wrong thing for the right reasons. And so he can't sign the Accords because he believes they are wrong, and he can't even *pretend* to go along.
The two sides aren't just "oversight" vs "freedom." It is also "practical reality" vs "principle." And the ending actually emphasizes this second layer of Team Cap and Team Iron Man. At the end of the movie, was Tony acting consistent with "team oversight"? No. He *was* acting entirely consistent with "team do what's necessary" - even, emotional that he was, at the *very* end. All along, Tony was a man driven by his emotions, his guilt, his belief that he had a responsibility he didn't really want but couldn't avoid because he had the power to address.
Although the ending is a little clumsy, it might have been unavoidably clumsy given time and narrative constraints. I think the ending is meant to make you think more about what these guys really stand for. The Sokovia Accords and the oversight issue were important, but I think they were just a small component of the larger schism between Tony and Steve. Tony is someone trying to navigate a complicated and ugly world through both daring and compromise, and he is ultimately driven by guilt. Steve is someone trying to navigate a complicated and ugly world by reframing it with his own moral compass, making the complicated world simpler, so he can try to always do the right thing for the right reasons. That's what the ending is all about. And I think the last scene with Tony is meant to show that ultimately, Tony knows this too.
Now, this should all sound familiar. The billionaire haunted by guilt and driven to always do what is necessary? The paragon of virtue that always tries to stand for the right thing? That duality is actually the modern Batman/Superman relationship (at least, prior to the last few DC reboots). Batman and Superman are often portrayed as not friends, but as opposite philosophies that respect each other. Batman thinks of Superman as a naive "boy scout" but also as something the world needs, and in particular the super powered world needs: an example to look up to. Superman doesn't always get the job done the way Batman would like, but he serves a greater purpose Batman never could. He makes others want to live up to his ideal. Batman doesn't want followers and pretenders, because he knows deep down that his moral relativism would only create monsters. Superman, by comparison, often sees Batman as too violent, too extreme, too willing to bend or break the rules. But he also sees Batman as incorruptible in his own way, and in many versions of their story Batman is the only person Superman trusts with Kryptonite. He doesn't just trust Batman to possess it, he also trusts Batman to be one of the few people who would actually use it if he felt it necessary. Superman doesn't just trust Batman with his life, he trusts Batman with his
death.
Somehow, perhaps without meaning to, Marvel has managed to hijack one of the best features of two of their most prominent characters. Where BvS fails most is that the fight is between two strangers: they don't know each other, they have no history, the fight isn't about anything. In The Dark Knight Returns the fight is about something: it is about a many-layered relationship they have had over the decades. It is about the different philosophies they represent, the current places they find themselves in, the respectful but adversarial relationship they have often had. It is personal in a lot of ways. The fight between Rogers and Stark is the same: it is about something: it is about a lot of things. The conflict between Rogers and Stark in Civil War evolves their complicated relationship, one of respect, anger, jealousy, and guilt. They aren't friends. They are brothers. And at the end, they fight like brothers. They aren't the leaders of Team Cap and Team Iron Man anymore. The conflict between them, and what happens afterward, is personal. It is what happens between brothers.
It takes a long time narratively to get here. In a sense, we've been building to this moment from the very first Iron Man and Captain America movies. I think it is important that you have these dueling personalities and philosophies, that your central characters have both a reason to stay together and yet a reason for conflict. The Superman/Batman relationship wasn't an accident: it was the best way to convey something that is very hard to convey: respect. If two people really like and agree with each other, it is hard to tell if they are cooperating because they respect each other, just happen to always agree, or just because one of them is willing to go along with the other. But when the characters aren't alike, don't always agree, actively disagree, don't even especially like each other
and yet work together that can very strongly convey the sense that they do so because they respect each other. They respect each others' character, judgment, and perspective. And when the characters respect each other, it makes it easier for us to respect them, particularly when it is earned. Friendship is easy to portray. Respect is much harder, but also more rewarding. Marvel has gotten Tony and Steve to the point where we can believe they respect each other, for reasons that are earned. That's something Warner/DC will have a much harder time getting to, because they rushed the relationship between the two characters that need to respect each other the most in their narrative. It is something I don't even think they realize the lost potential they threw away by trying to catch up with Marvel.
That's what I think the ending is all about. When you think about plot, and narrative, and structure, and pacing, and cinematic principles, the ending can seem abrupt and disjointed. But if I ask you this question: where is Cap now, in terms of his character? Where is Tony, in terms of his character? Not their physical locations, but their characters. And what is their relationship now? I think most people have answers to those questions that I don't think they would have had if not for the final ending sequence. And I think that's more important in the end. Heading into Infinity War, and perhaps more importantly beyond it, setting this up was very important, and could pay off huge dividends in the stories to come.