I devoured this entire story so far over the last few days, and actually registered on this forum just so I could tell you how awesome it was. I'm a big fan of alternate history, but the pickings of real quality work are pretty slim IMO (I even find a lot of Harry Turtledove's work to be pretty silly sometimes). But this is everything I look for: a single allowance of a far-out concept to get the story rolling, followed by a thoughtful look at what the repercussions might be.
A few others have asked what's happening with various real life figures, and there's one that hasn't been addressed yet that I'm a bit curious about: Alex Haley. His early successes (writing articles for Playboy (including an interview with George Rockwell!) and co-writing The Autobiography of Malcolm X) have already been taken from him, so there's no way Roots is in the future even without regarding the shattered race relations. But what has he been doing instead?