The villains need to have some opinions with meat on their bones. The reader can agree or disagree, but the reader has to be able to believe the villain believes.
If Evil Bob is out doing bad stuff, Evil Bob has to be able to tell the reader why he’s doing bad stuff. I read way too many books where the villain is doing bad stuff, interesting bad stuff, but I never believe Evil Bob is doing it for any reason other than to make a plot.