"Our role in this review was not to second-guess discretionary judgments by Department personnel about whether to open an investigation"
Hmm, I'd have said that was exactly their role. If your job is to review FISA applications then the decision to open the investigation is vital, based as it appears to be on incredibly scant gossip.
Horowitz didn't interview Mifsud, but Durham did, time will tell how chatty he was. The TDS afflicted will accept and attempt to justify literally anything that undermines President Trump but, like the shampeachment, FISA surveillance because Orange man bad sets up another dangerous precedent for future abuse.