As with everybody else - this is just my opinion.
On TV, Movies and in books - I truly hate the UberVillain.
The guy who seems to be bad for evil's sake and is rather like an ebony Energizer bunny always
coming back again and again and making the good guy(s) dance to his or her tunes.
Red Jack on the Mentalist, whoever killed the lady police officer's dad on Castle, Jack and Jill from the Profiler. (I truly hated that show because it seemed to me - to be about some sicko making the profiler play his twisted game. It was, in a sense, a form of rape and, as I said, I dispised it.)
Kay Scarpetta by P. Cornwall has had to deal with that kind of UberNut.
I've written different kinds of villain sdepending on what I needed. The female villain in my big work is a business woman from a culture where woman aren't usually business CEOs. This has made her cold and ruthless and driven to succeed but she has a reason for what she does - not usually motivated to torture or maime. Her second in command is male, outspoken, and not involved with her. (Didn't want villain and second being a couple - doesn't always work so well.)
The hero is picked to be the scapegoat for a horrific crime simply because he's not impressed by her, nor seducible by her and is something of a leader among the others of his station.
Conversely in another story - the villain, again female, is bat-shit crazy but very smart - and very, very driven - she does like to torture and torment.
(Hmmmm, just noticed I seem to have several female villains - Not so sure what that means.
)
The Sociopath works for some villains and the driven/going about it the wrong way works for others.
It's what you need your villain to be and/or do that's gonna shape what you create.
I do agree with not being graphic with violence - I don't need to read 30 pages of blood and guts. For some they like that kind of thing - I don't. You can show/illustrate violence without soaking the pages in blood and body fluids. Like in the first hellboy when the old professor is killed - you see a splatter of blood on the bible - not a lot of dwelling on it. More poignant and more powerful.
I will say that I once heard an actor who often played villains say that playing villains was more fun than playing heros. Because a hero is constrained, usually unless it's an anti-hero, to a certain set of actions while a villain can be anything from good to pure evil.