My guess is that it will increase enthusiasm among Clinton's supporters. Trump has less money, no field operation, no endorsements, a Jonathan Franzen novel's worth of unprecedentedly stupid/ignorant public remarks as POTUS candidate, 3 debate losses, and so on, but he remains afloat for two reasons: astronomical levels of structural political polarization (essentially guaranteeing the the R and D will earn at least 40 percent of the vote each), and core supporters who are invigorated by more grievance than I've ever seen before. Economic grievance, racial grievance, real complaints, imaginary ones. They are an incarnate clot of identity and grievance politics, and they are absolutely brimming with bitter anger.
The feeling that their candidate has been hamstrung by the FBI may endow Clinton's core supporters with a little of that fire. As for whether the letter itself hurts with undecideds, beyond a 3-day tightening in the polls, minds are not going to be changed in significant numbers by "we have more emails to look through to determine whether or not they affect the conclusion drawn from a prior investigation."
As for the thread topic, I'm on board with TB. O'keefe should have at least one more video, and Trump will take at least two body blows by the weekend.
As of now, Clinton wins handily. Even if it were close going into election day -- and note that it isn't actually close when Virginia and Pennsylvania are not considered real battleground states -- her enormously superior field organization will deliver her the presidency. Furthermore, the early voting numbers I've seen for NC and Nevaaahhhhda support the conclusion that she will have a strong firewall in states without which Trump is in existential trouble.
The lesson in the end will be this: if you want to win an election, don't nominate a sociopathic nut with a room-temperature IQ. If you don't want to nominate a sociopathic nut with a room-temperature IQ, purge your house of racists and loons. The GOP's decent forty percent lost this election to its indecent forty percent. That's all.