If there’s one real detriment to the Marvel Cinematic Universe, it’s the fact that it hasn’t necessarily developed its villains as well as it should.
There have been one or two instances where a villain gets an arc that extends over multiple movies — but really, only Loki (Tom Hiddleston) has had an impact on the MCU, primarily because Joss Whedon used him for The Avengers.
This is exciting, for various reasons.
Taking a page from the James Bond universe, each new movie tends to introduce new villains that have direct connections to the heroes, be it Kaecillius and Strange, Zemo and Captain America, Vulture and Spider-Man, and Yellowjacket for Ant-Man.