Hi: Let me say upfront that I have been a sporadic participant in FlyerTalk (both as a member, and prior to that as a lurker); depending on my work and travel schedule, I sometimes check it several times a day, and sometimes not for months at a time (as has been the case recently). I'll also confess that I have only skimmed the previous 13 pages of this thread, so apologies in advance if I am repeating something that may have already been suggested. With those caveats, though, I thought perhaps I might be able to offer something from my perspective as a somewhat 'average' member.
First of all, I very much appreciate the fact that FlyerTalk IS a moderated forum -- it's what keeps the discussion and information here useful. For that reason, I very much appreciate all the time devoted by the volunteer moderators (and TalkBoard members) to keep things running smoothly. And for THAT reason, while I would hope that most moderators are reasonably responsive to community feedback, I would really disfavor adding a feedback mechanism that requires yet more work for the moderators, or creates a disincentive to moderate, because it becomes a public bully pulpit.
For the most part, I think that the ability to PM a moderator provides an adequate channel for feedback about specific issues as they arise. It also puts more onus on the member providing the feedback to do so in constructive and clear terms -- I think it is much easier to complain about someone on a public forum than it is to their face.
However, I think it is equally true that there can be some benefit to public discussion of issues regarding moderation -- e.g., when one person states "I'd really love it if the moderators did x," and someone else chimes in to say "I never thought of that, but now that you mention it, that's a really great idea." Though not perfect by any means, a public forum can also provide some gauge of how widespread support or lack of support for a particular suggestion may be.
Bearing these two considerations in mind, here is my suggestion: instead of having an ongoing thread for moderation issues in each forum, how about having a limited-time thread (e.g. 2 weeks) posted on an annual basis to collect feedback -- i.e., similar to the way in which polls are posted for a limited time. There would need to be ground rules, of course, that keep the tenor of the discussion civil and not personal. But I think a once-a-year thread would encourage the posting of more general suggestions rather than complaints about specific moderator actions. It would also limit the burden on moderators of having to sift through a thread. Perhaps, if desired, sometime following such exercise, the moderators could post a message providing their own feedback on some (not necessarily all) of the suggestions offered.
Anyway, just a suggestion. At the end of the day, as someone who benefits a lot from this forum but does not have any responsibilities for running it, I'm willing to live with the rules that the moderators and the TalkBoard set up -- including the rule about not discussing moderation decisions publicly -- even if I may sometimes disagree with individual moderator actions. If I didn't feel that way, there are plenty of other internet fora to explore. And I've never felt that a politely worded PM to a moderator would be unwelcome as a means of feedback.
Good luck, and sincere thanks to everyone who works to make FT a better place, whether in an official governance role or making constructive suggestions. It's a very interesting community.