2. It Actually IS About Registration
When it was first revealed that the Superhero Registration Act was being renamed the Sokovia Accords, it was assumed Marvel were swerving registration in legislation relating to control: when a superhero could be sent to another country and what they were allowed to do. Boring, and less catchy, but it made a lot more sense in the wider context of the MCU, because convincing a U-Turn would be remarkably difficult. But it looks like Registration remains a big part of the Accords: their front cover has the sub-heading "Framework for the Registration and Deployment of Enhanced Individuals." So the suggestion is that the government wants to take a roll-call of all of the superheroes operating in the world, in the interest of control and accountability. It's still more likely that Bucky is a bigger driving wedge between Cap and Iron Man, but the confirmation of superhero registration is a massive one - as much for the problems it causes as the intrigue. And the suggestion is that superheroes are going to be underground or enforced heading into their Phase 3 movies.