I really didn't think any of the "villains" were that villainous... I mean, Szeth SEEMS the worst, because he mows down people for what some might say is "no reason at all", but he clearly, and I mean, really clearly, can't control himself. The Oathstone literally forces him to do things. Maybe in a realistic novel, where some murderer is saying "my Oathstone made me do it" would be wacky, but in a fantasy novel, its completely acceptable, and I for one am very excited to see how Szeth's character plays out. I don't think he is, or ever will be, entirely, a villain.
The other characters you talked about were d!cks, I'll admit, but none of them were that villain from a comic book, who does evil stuff just to be evil. I think we have yet to see who the real villain of WoK is. Although only mentioned a few times, Odium does seem to have influence (much like Ruin) on the people of Roshar. I have a feeling he will be showing up a lot more often in the future. Most of the people did what they did because it is the best way for personal gain, which is repeatedly shown to be core of Alethi culture.