You're pretty much right!
One of the most F-ed up villains I've read is Jagang from The Sword of Truth series. Though I don't like to copy other people's work, I think he's a good model for what qualities a villain should have.
He's got a vivid personality. For instance, he has verbal quirks that make him creepy like calling women darlin'.
He think's he's the good guy in a really twisted way though he's obviously the most F'ed up guy ever. He even tries to rationalize and justify himself as a genuinely good person who has the big picture in mind for the world.
He is broken (uber powerful). A good villain should have specific abilities that make him/her hard to defeat, especially if it's fantasy. This particular villain has the ability to make his way into any person's mind no matter where they are in the world, unless they've sworn allegiance to the protagonist of the story, who has a magical protection in his bloodline to protect his people against this type of villain. But yea, he can pretty much control the whole rest of the world using his mind alone.
Fearsome. I think especially with fantasy novels, one trait that they all share is that the villain is feared among the commoners. In turn, the villain basically has the public by the balls, keeping noblemen corrupt and everyone else afraid to do anything about it. (Though some are still willing to stand and fight)