I think you're right about this that disbanding them goes too far, but we could certainly use significant reform.
In particular, they often use 18 USC 1001 to manufacture crimes and the only evidence supporting a charge may be a written report (an FD-302) that could have been written months after the fact. Their current policy is not to record interviews. I think that needs to be reversed and there should be some materiality requirement to the 18 USC 1001 charges, rather than trying to get someone to slip up. They should also have bodycams when involved in raids or similar activities, same as cops do.
I'm also disturbed at how often they "lose" things like Woods files. I think their case files should be externally managed and backed up and audited by a separate agency who can present "missing" evidence in court from backup, along with records of who tried to delete it, regularly audit case files for things like the missing Woods files that shouldn't be, etc.
I'd do the same for cops, too. Body cameras should send the video to a separate organization that doesn't answer to the cops, so they can't "lose" it. And if they "forget" to turn it on, well, that should be subject to regular audits and should get someone in trouble long before it becomes an issue in a big case.
It's weird, we spend lots of time designing computer systems to support accountability, but there seem to be a lot of things we could do better on that front in law enforcement.