Disney stepped in during the time the first Avengers was being made. Pre-Disney, the only good villain we got was Loki. Post-Disney (and, albeit, after a long start), we got Zemo (maybe an honorary mention, but a good start), Ego, Vulture, Hela and the Grandmaster (maybe not as deep characters, but well-executed in terms of being memorable and well-defined), Killmonger, Thanos (technically introduced before, but was actually fleshed out here), Ghost and Talos (technically not villians, but well-written antagonists), and Mysterio. (Also, Nebula deserves a nod; while not a villain, her path to redemption was very well plotted, creating a very multi-dimensional character.)
Now, that might be more credit to Marvel Studios then Disney, but it is observable that the MCU started getting consistently good villains under Disney's management. Make of that what you will.
Whatever you say.