Ask Manor Club management if they are willing to allow you to post a message somewhere at Manor Club that other owners will see. If you show them that the group intention is to increase owner awareness, and not to promote resort bashing, maybe they'll go for it.
Maybe in the marketplace, or in the lobby, or at the concierge desk above the wall of pamphlets. Even better would be in the information panel in each of the elevators. Then everyone will see it.
I don't think Marriott would ever allow this. The last thing they want is to have their "dirty laundry" aired publicly. (Hopefully this is figurative, and not literal.

) At any rate, Marriott certainly does not want to give owners, exchangers, and/or guests an open invitation to a forum where people are going to list their concerns about the resort.
Think about it. No business would want this...especially in the hospitality industry. Perfectly happy owners and guests finding a web address from a posting in the lobby or elevator, going online, and finding a discussion of things that are "wrong" with the resort. Suddenly content owners and guests become discontent. Little things that they never noticed become big issues.
Even positive posts on an open forum can be hazardous. For example, let's say someone on the forum had stayed in one of the huge three bedroom villas in Berkeley Manor that most owners don't even know exist. They loved it and posted all about how fantastic it was on the Marriott owner's forum.
Joe and Mary Owner are currently staying at Manor Club. They were perfectly happy in their typical two bedroom villa in Governor's Manor until they saw the Marriott owners forum advertised in the lobby. Now they've gone online and found out that not only are all the Berkeley Manor villas larger...but there are a couple of huge three bedroom villas in that building that are given to two bedroom owners each week. (All villas were sold as floating two bedroom ownerships at Manor Club. The three bedroom villas were not sold as such.)
Now Joe and Mary are discontent and march right down to the resort manager's office. They demand to know why they weren't given one of these three bedroom villas. After all, they own four weeks, purchased directly from Marriott, and have been loyal owners for over eight years.
In contrast, they read on the Marriott owner's forum that the people who got the three bedroom just bought their week last year on eBay...and only paid $7500. Joe and Mary were happy, but now they are furious. Why did those people get special treatment? Not a good situation.
Steve