A large number of auditors use the mechanism of OFI's to "add meat" to the bones of an audit. IMO it is almost impossible to write an OFI that is not a non conformance.
I think that really depends on the auditor's experience other than "auditing ISO". Two examples from my current auditor (from DNV, hi Sidney

):
OFI in the supplier control area. We have a lovely database for tracking Supplier [corrective mostly] Action Requests. Said database was reasonably up-to-date. Specific non-conformance against timely update of the SAR database was not supported. OFI of database update. This was a good call and no "official" suggestion was made; just take another look. We ended up building a monthly review into the Materials Team's regular meeting. Closed feedback loop.

OFI for safety. Due to auditor's extensive safety compliance experience we were given an opportunity to take a look at safety training regarding overhead lifts. The lifts were on our PM list for maintenance but there were no specific training records for how to use them. Again, no evidence to support an QMS finding against the standard but this saved us a potential OSHA compliance issue.
o by identifying problems which, if resolved, will enhance the organization’s performance.
o by identifying improvement opportunities and possible areas of risk
Examples of each above. What's wrong with that. Hiring a third party is expensive. I certainly hope that I can get more than an audit report and a fancy certificate.
I used to write a number of OFI's during each audit, but have stopped. The Clients felt they were very useful, but the CB's I work for are obeying the pressure from ABs to not write OFIs.
It is an oxymoron - the audit process is to drive improvements, but we cannot recommend improvements...
I say write them and leave it to the auditee to decide which they find useful.
The AB's are out of touch with reality. You better be doing something more for me as a registrar than filling my Improvement System with BS (barely supportable) findings so that you can meet some arbitrary quota of findings per audit.
Perhaps, one day, you will have the privilege of being audited by an experienced, good auditor who provides value and good recommendations. It sounds like you have not had this opportunity yet.
May I suggest that you interview a couple from DNV?
Consulting - when an outside person recommends/suggests (and implements in some cases) methods on how to do something.
In my case, he is very careful to NOT recommend methods on how to do things. He simply informs me that a process should be reviewed for possible improvements. He has not once used the "An another facility, I saw that they did X to resolve this" or "Creating X would greatly assist you" or "Automating this would resolve the errors in this area" or "I noticed a great deal of duplication in this area"...etc.
I do realize that many auditor may(do?) cross this line. My current external auditor is very careful not to.
As is mine. We appreciate not being told how to do it. We appreciate being given a heads-up if the auditor sees something that has caused someone else grief. After all, these folks have been in scores of different plants and seen a lot of different things. I can't imagine someone like Randy (with an obviously colorful background) overlooking a serious issue in a plant just because it wasn't an "ISO" finding.
Finally, let me say that honey catches more flies than vinegar. Is their anyone out there that doesn't believe that auditors are human? If they point out an issue for your benefit, I have to believe that you receive some good feelings from the auditor when they appear at your doorstep and see that you have actually listened to what they said and made some improvements based on the opportunities that they have pointed out to you. Were I a third party auditor, his kind of attitude would certainly make me more inclined to believe that your QMS seeks to improve via input from any direction, rather than you wishing to receive only a PDF file full of fancy logos stating that you are compliant.