It confirms what we assumed all along: (1) prior to seeking the warrant and to Comey issuing his letter, the FBI had no idea whether these were new emails, or duplicates of emails they previously reviewed--all they could see was non-content header information (to and from); (2) the FBI had no information to suggest that the emails were improperly withheld from them previously; and (3) the FBI had no facts to justify the urgency in seeking a review of the emails prior to the election. This latter point is key. Generally, DOJ policy commands that prosecutors and agents refrain from taking investigative steps (even non-public steps like seeking search warrants) within 60 days of an election in a politically sensitive matter.
Bottom line: nothing new, no urgency, no obstruction, no reason to defy longstanding DOJ policy and risk affecting the election. And there was simply no basis for Comey's decision to make matters worse by issuing a public letter to Congress.
If the prospect of a Trump-appointed FBI chief weren't so scary, there is no question that Comey should be unemployed right now.
The last point is the deepest irony. Comey should be out of a job. It's that bad. But I would argue that it would actually be a disaster if he didn't serve at least through the next four years. Everything we've seen about the incoming Trump administration suggests they'd appoint someone to run the FBI who would approach the job as the president's personal and political enforcer. Comey made a terrible decision. I'm quite open to the idea that he did it because of his personal bias against Hillary Clinton. I think it's even more clear that he did it because he could not control politicized elements within the FBI.
For all that, the alternative would likely be much worse. I don't believe Comey is a crook and I think he believes in the rule of law. So he becomes the paradoxical beneficiary of his own shameful decision.