The unredacted version is really interesting historically, but I don't think it reveals much more about the lengths the FBI went to. I believe it was already well-known and believed that King was being sexually blackmailed specifically. The redacted portions all seem to deal with that exact nature of the blackmailing.

The redaction reveals more about what the FBI wouldn't do: how at least one person was reluctant to release public documentation proving that's what the FBI did.