The FOIA requests almost always results in a lawsuit. Mostly because of the government refusing to give up the documents or because of over redaction. And almost always we win over the government. So whoever did the FOIA request should have sued to have he judge review the redactions. 9 times out of 10 the redactions were not justified.
Having been on the "wrong side" of FOIA requests a number of times, it varies.
First is a legit gripe, but there is sensitive info files/correspondence. Tough one there and takes a LONG time to review what can, should, or needs to be redacted.
Second is a legit gripe, but between two parties and FOIA request to a third party caught in the middle by the sides trying to prove a point.
Third was a PURE fishing expedition. Asking for info under guise of "save the fishermen of Okinawa" and asking for "anything and everything" to do with something that has NO impact on the subject, but name of project/effort/study was mentioned once in a report. That one was easy to defend.
Overall, FOIAs are a huge PITA, but I can understand the need, utility, etc.