How come Steve and Natasha go to Falcon for help instead of the Avengers?
They know SHIELD has taken over HYDRA, is planning something global in scale, and that they can't trust anyone. It seems the first people they would contact for help are Stark/Banner/Clint/Thor instead of Falcon, who they knew for even less time.
I know some people had the same problem with IM3 and Thor 2 (personally, I didn't) but it's a bit different this time because we actually see the protagonists in search of someone they can trust for help.