I'm just going to be right out with it, though: Ant-Man and Spider-Man were both completely irrelevant to the plot of this movie.
They were basically just thrown in to up the roster count for both sides. To be honest, I almost wonder if it would have been better to not have them at all. Not that they didn't have a cool fight scene, not that they weren't funny, but they did distract from the real story for a bit.
Spider-Man kind of came out of nowhere. Maybe if there was some allusion to the fact that Tony had seen his YouTube channel earlier in the film it would have helped the flow a bit more, but the movie just kind of was like, "Here he is!" I mean, at least with Ant-Man we had an entire movie to introduce us to him and let us get to know him, and a connection to Sam that helped act as a segue to fit him into the plot. Spider-Man just kind of got pulled in, and quite late in the game, too. I'm not sure how I feel about him being introduced like that.
Not to mention, the real break-out star newbie here is Black Panther, and I wish we could have had more of him. In the end he became the voice of reason to end the cycle of destruction. I was very happy with the character development he was given in this movie; how he had spent so long tying to kill Bucky, only to realize the need for vengeance was the cause of everything that happened and in turn served to make him choose to not take the life of his father's real killer. Chadwick Boseman nailed it. He was simply perfect in this role.
Anyway, that's all I really have for now. I have more thoughts, and some stuff I ponder about Ant-Man, but I'll save that for later when it isn't 12:30 am.
Also, I have a massive theory about the title of the Spider-Man movie concerning something that happened a couple of times in Civil War. I'll talk about that in the Spider-Man thread, though. I'm sure you guys must have caught it (first time it happens is in the very beginning)