Still sticking with my idea that a faction of the MSM and Leftist/DNC establishment now knows Clinton is cooked by something maybe in the Wikileaks or other disclosures, and is cutting their losses.
Or that there's accurate internal polling that shows Trump is ahead, and they want to make this about "Hillary the bad candidate" they can blame, rather than "The entire DNC. The bad party and ideology America doesn't want."
I suppose it's possible that internal FBI politics, or a sudden attack of conscience alone has forced Comey's hand, but considering how blatant the whitewashing of Clinton was for first email/SCI violations, I kind of doubt it.