I was trying to find a discussion on Buddha to add to, but seems the major discusssion has been hardcover, softcover and who's finished it. It just happens that I had trouble locating #5, and after quite some time started over.. So maybe I'm behind you all.
As I read in Buddha about the shudra and pariah, I can't help but think of Japanese's analogous group, the Burakumin.
Outside of Japan, people are not well aware of Japan's "status discrimination".
My feeling about Tezuka is that he was a social provocateur. I could believe that a major reason he wrote Buddha, and especially the style in which he did, was to make people think about social discrimination and the maltreatment of the Burakumin in particular.
David