(quotations may be exaggerated for dramatic purposes.)
Vincent said to me: "The point of Dogs is that you go in thinking you are heroes, and you realize that you're playing the bad guys."
I said to Vincent: "The point of Dogs, to me, is that you go in thinking you are bad guys, real zealots, the SS or the inquisition, and you realize that you are actually good people, trying your best."
Every satisfying character arc I have ever had has played out this way -- at the start, the person is a caricature, and they become human in terrifying and startling ways. I see this in character arcs, written across my past -- Raidant, Takam, Eric, Mike, Kent, Mark, Cyrus. They began as form and became as substance.
The joy of this play, the process of this play, the inescapable purpose of this play is not the creation and celebration of these mythic types, but the destruction of them.
I do not believe it is possible to play an RPG character without eventually becoming aware of them as a human being and, by coincidence, destroying their "archetypal" role as a hero or a villain. (Archetypal is in quotes because I want people to know that I don't mean archetype in any sort of Jungian or Campellian sense {spoon. me. gag. with.} but rather in the literary sense.) This development of this compassion (in equal parts sympathy and disgust) is central to RPGs as a tool for moral development.
Which is what they're for.