This movie does require many superheroes, as it encompasses all the Avengers in the comics. While we have seen enough heroes and villains in the movies, I was also hoping they might include people from Agents of S.H.I.E.L.D. or Daredevil. Matt Murdock might have been called to attention by the Registration Act, as well as Deathlok showing up just because he is a cyborg.
The development of this plot line has been seen throughout previous movies. In Avengers: Age of Ultron, many civilians have been seen protesting the Avengers' interference which usually result in massive casualties and property damage. In Ant-Man, Hank Pym shows contempt for the Avengers, mentioning that they're too busy dropping cities out of the sky. The World Security Council had also pushed away the Avenger Initiative in favor for Phase 2 prior to the War for Earth, as well as many governments around the world displeased by HYDRA's infiltration of and the collapse of the intelligence agency S.H.I.E.L.D. S.H.I.E.L.D. itself had its own War against the Inhumans and the people of Hell's Kitchen also sided against Matt Murdock's heroic but unorthodox actions. While most of the animosity is towards individuals such as the Hulk, who's rampages destroy cities like Harlem and Johannesburg, or Tony Stark, who's fortune was amassed by the manufacturing and selling of weapons, or the Devil of Hell's Kitchen, who's shady appearances and actions disagree with the public's view of justice, the public will no doubt push for safety and turn against all heroes.
At the end credits scene of Ant-Man, Steve Rogers and Sam Wilson are seen with Bucky Barnes, who was found and brought to the New Avengers Facility with his arm entrapped. They discuss bringing in help, but they decide not to call Tony Stark. This is a set up for the events of Civil War.