Spoilers for all the Marvel Cinematic Universe follows.
The Marvel Cinematic Universe is, arguably, the most lucrative and popular franchise nowadays. It's amazing to see that in just six years, Marvel Studios has positioned itself as one of the most trustworthy studios and its brand is synonym of good super hero films. There plenty to enjoy in Marvel films: exciting action sequences, good humor, the shared universe, epic battles, etc. But, if there's one thing that is the weak link in most of its films is the villains.
With few exceptions, the Marvel villains tend to be one-note and just stay for one film. The sense of peril is not very high and the films succeed mostly because all the other elements that compose the film work much better. Let's take a look at the most recent example. Ronan the Accuser in Marvel's latest film, [Guardians of the Galaxy](movie:424073). The film is a blast from beginning to end and it's one of the studio's better offerings. The cast has great chemistry, the humor works very well and the effects and action sequences are amazing. However, Ronan is just another madman that wants to conquer the world. There's not nuance in the character and his personality is just flat. Thankfully, the film works so well that Ronan's lacking personality does not dampen your enjoyment of the film. And this happens in almost all of Marvel films.
Most of the villains are hell-bent in conquering or destroying the world but there's no inner motives for that. They just want to destroy it because they are evil and that's it. Obadiah Stane, The Abomination, Malekith, Ivan Vanko, they all come and go. They make some destruction but they are ultimately defeated without making a dent in the story and in the whole cinematic universe.
There are some exceptions, however, that shows us that Marvel can do good villains. By far the best is Loki. Loki has appeared in three Marvel films (Thor, The Avengers and Thor: The Dark World) and he is still alive and well so he will appear again in the future. Here's a villain that has a nuanced personality. Yes, he is evil but also he is conflicted and has much more going on that just "wanting to destroy everything". He is cunning, smart and charismatic and he feels like a real threat (it took all the Avengers to stop him) so he is a living proof that Marvel can produce great villains. Another recent great addition is Alexander Pierce from Captain America: The Winter Soldier. He has real motives to do what he does and his threat left SHIELD in ruins changing the whole landscape of the cinematic universe. He died at the end but he left a deep impression in the Marvel canon. To a lesser extent The Red Skull and Aldrich Killian had also more personality than most of its counterparts. Both Loki and Pierce added another level of enjoyment in their respective films that the others lack.
Marvel is doing great business by producing high quality entertainment but being at the top also mean they need to up their game. Ultron is the next villain and he looks real cool and menacing but we really need to see how threatening he will be to the Avengers. Marvel needs to give him a real personality so we can be even more invested in what's arguably the biggest film of next year (alongside Star Wars).
And of course there's Thanos, who has been teased as the real deal but is still working in the shadows so far. When he finally steps into the light (possibly in Avengers 3), he has to be the best and most threatening creature in the Marvel Universe. We need to see his motives and we need to invest in him as a character. Marvel must know that when it comes to Thanos, failure is not an option.
Marvel has proven time and time again that they can produce high-quality films. They are willing to take risks and are not afraid of trying different genres in them. Most of their films are great and that's why they had gotten away with unappealing villains. However, there's also evidence that they can create great villains and I hope that, from now on they will give them the same time and care they give to their heroes. The films and the audience will benefit immensely from that.