It's all about who is in control of the DOJ. The #2 Rod Rosienstein (Bad Actor) is the one who (officially) calls the shots at the FBI - thus we need to get rid of him. The OIG Report (Original IG unredacted) is how/when that happens.

But while RR is getting canned with the final OIG report I think cleaning up the government is more complicated than just the DOJ. It's hard to appreciate just how many people are getting canned every day from all 3 branches of government.