5. Ronan The Accuser
It's no secret that Marvel has a villain problem, and this list could have very easily comprised solely of names like Whiplash, Malekith, Yellowjacket, and pretty much the entire Chitauri race. However, one of their biggest mistakes came in the otherwise excellent Guardians of the Galaxy. Ronan the Accuser has fought as both a hero and villain over the years, and he stands out as one of the emotionally complex characters in the cosmic side of the Marvel Comics Universe. The movie version? Well, he was a psychopath who wanted to kill everybody, and that's pretty much it. Like most Marvel Studios villains, he served his purpose in the sense that he gave the heroes someone to go up against, and while that may have worked slightly better in some of their other releases, it wasn't the case here. While it was foolish of Marvel to not give him a chance at redemption in order to become a key part of this franchise moving forward, even more frustrating is the fact that they didn't really commit to making him as truly evil and despicable as he should have been. He never had that one big moment which would have set him apart from other bad guys, and making him Thanos' b*tch certainly didn't help either. In all honesty, Lee Pace really could have been cast as any generic cosmic Marvel villain as nothing beyond Ronan's Kree heritage and that fancy hammer of his really resembled the superior comic book version.