I feel like many mangas have a difficult time showing characterization post-villainous-reveal.
I would want the villain to have all the traits they've been established to have, just with an overarching need or motivation that puts it into context. Instead they often get flanderized into one of very few archetypes, like the Blood Knight, the 'Do it for the Evulz' guy, the Mad Scientist, the Well-intentioned Extremist, and the Evil CEO.
OK, I don't need a multi-chapter flash-back for every single villain, but it just seems like that's the only way for the author to realize that the villain is a unique human being too. Can they, like, maybe write the flashback arc and then trash it afterwards, keeping just the characterization?