FifthView, think of Jamie and Cersei from ASOIAF. They were absolutely villains in the first books until we saw their POVs in the later ones.... their POVs were still pretty twisted, but it was enough to develop a sense of complexity to them, so that "hero of their own story" thing kind of applies. That's why I think, the more complex the villains, the more it requires them to have a POV for that to come across. And that one question, does your villain get a POV?, is a big one that really shapes the nature of the whole book on its own. It's got to be the kind of story you want to tell after all.