Substitute Troll said:
Alduin was a terrible villain. Why? Because we were forced to believe he was the villain, and he was abscent most of the time. And because he had a ridiculous voice.
Letho was an awesome villain. Why? He had a reason that wasn't fucking retarded (herp derp I want to control the world), he wasn't evil per say and he was almost always around the corner. Plus, he was a fucking badass.
Very true, for me in recent memory, Alduin is the worst villain I have seen for a long time.
Reasons:
1) He hardly appears. We see him right at the start, once not far in then don't see him until the badly paced ending.
2) His plan has no complexity. Alduinss plan is so basic thats its just 'Bring back dragons so we can kill everyone because thats what I did before.'
3) There is nothing interesting about him. Alduin is a magic dragon, that makes him a bad guy. The worst reasonings of why the world nearly got taken over is because 'A magic dragon did it.' or 'A wizard did it'.
4) We never get to speak to him. Alduin does speak to us at one point where he just insults the player. Dovakhin never gets the chance to talk to Alduin so encounters amount to 'There you are! Lets fight now!'
5) The player is destined to beat him. No only is Alduin an awful villain, Dovakhin is an awful protagonist. Its their destiny to beat Alduin which means they are stuck with Alduin, while being the mythical Dragonborn overrides anything the player may achieve in game. Fame and hero status should be earned through deeds, not being born with it.
Conversely, Caesar is perhaps the best villain I've seen in a game for a long time. I know he doesnt have to be the bad guy but thats one of the good things.
Reasons:
1) You can talk to him to learn his motivations. Caesar approaches you with an offer to meet him, he also offers a pardon. This is a great chance to have an audience with a major character.
2) You can decide to join him. You should never fight the villain without having a good reason for it. Caesar gives you plenty of reasons to oppose him, but there are reasons and the choice to join him. This allows the player to make their own mind up if he is their sort of villain.
3) His influence is present, but he isn't always. In the Mojave the Legion is talked of often, townspeople tell you rumours they have heard and their opinions on Caesar and how he compares to other big powers in the region. The player gets information to become aware of the villain and will later see how he excercises his will to be able to judge him.
4) You can learn more about him by talking to people that have witnessed his actions. Raul the ghoul is a great example of this, having witnessed just what Caesar can do and by learning this, it elevates his motivations to a much more noble goal achieved with evil means. The player can get a more impartial opinion than NCR soldiers or Legion warriors. Speaking to Followers gives another indication of how Caesar became who he is and why he does what he does.
5) Caesar isn't the worst of the worst. Lanius is. The main villain in most of the endings isn't the most evil guy out there. The player can learn that he is the lesser of two evils as he keeps Lanius in check and can do things Lanuis cannot, such as keep a nation together and respect his foes.