I think his villains are more neutral evil than any other alignment. While I understand that he may be making a point that only the Dark One is truly evil and that humans can't even come close, the sad fact is that there are evil men and women in the real world, and his inability to show or bring that level of inhumane depravity to his villains keeps them in the "stock villain" category, which unfortunately relegates the entire series to a lower status.