MCU villain hate is WAY overplayed Iron Man 1- Obadiah Stane was pretty solid. Jeff Bridges was often cited as one of the highlights of the movie
Iron Man 2 - Okay, Whiplash and "MC" Hammer were terrible....
Iron Man 3- While I didn't mind the comic twist on Mandarin, Killian wasn't good I'll give you that
Thor 1- Loki was excellent.
Thor 2 - Malekith wasn't great but Kurse was pretty cool; if fleeting.
Captain America 1 - Red Skull was great. Hugo Weaving did a great job bringing the Nazi A-hole to life.....though it sucks they got rid of him.
Captain America 2- Winter Soldier as the antagonist was amazing. Also, Robert Redford did a hell of a job as Alexander Pierce.
EDIT: Civil War - Zemo was really good, Crossbones was fine until they killed him.
The Incredible Hulk - Thunderbolt Ross played by William Hurt was solid; and Emil Blonsky (Tim Roth) was pretty good until he turned into Abomination.
Avengers 1- Loki again shined; but that's not surprising as Hiddleston is amazing.
Avengers 2- Again, Ultron was pretty good, certainly one of the better Marvel villains imo. He wasn't great, but I'd say he was good enough.
Guardians of the Galaxy - I actually liked Ronan, I just felt he was wasted by them killing him off at the end. Also, he didn't get quite enough screen time. But I like Lee Pace's take on the character. He was a badass and one can't blame him for succumbing to Chris Pratt's pelvic sorcery.
Ant-Man - Yah, okay, I couldn't stand Yellowjacket. The epitome of a throwaway villain from the MCU. The only real stain on an otherwise great movie.