The government just don't address the Vision situation. Ultron nearly dropped a city on the planet and Ultron 2 is running around with a universe altering stone in his head. Why are they OK with this? Why haven't the government sanctioned him for at least study?
The Sokovia accords is a good way to initiate the rift, though I think it doesn't do a good job with Cap, you have to link a lot from the previous movies to accept it. But it's not enough to get to a full contact fight. If Cap or his team had killed Rhodey that would have sent Tony into a revenge rage and that's enough. But they weren't brave enough to end the movie with Cap and Tony on opposite sides. Cap's letter to Tony basically healed the whole misunderstanding. It was just a very weak way to script what should be "War". It wasn't a war and the airport scene was just a fun skirmish. It needs to feel like people can die or it feels lifeless. And the fact that no one even came close to a death situation (Rhodey is almost walking again in 15 minutes of film time) is a huge miss for a movie like this.
I think overall the Russos poorly handled the amount of characters they had to deal with. I bet in about 2 weeks after the opening weekend cheering dies down a bit and level heads look again at this movie the flaws will be significantly increased because they are at the core of the movie. It's a shame, I loved CATWS so much, but this was a bit of a hollow ending to the best trilogy in the MCU.