I think it's useful to categorize the different types of complaints.
1. Dissatisfaction with the program rules.
Maybe you don't like the travel package rates, or the recent re-categorization of hotels, or that LT titanium is no longer achievable, or the absurd complexity of the breakfast benefit, or the capacity control on reward nights at a majority of hotels. Valid complaints all, but every hotel chain will have their own set of issues. "Bonvoyed"? I'd say no.
2. Failure to deliver on promised benefits.
This is a biggie. This covers everything from IT failures, missing stays or points or certs, hotels not honoring elite benefits, excessive time to respond to emails/calls and to resolve issues, and so on. "Bonvoyed"? Definitely.
3. Communication issues.
This includes complaints from folks unaware of program changes. I'd say the fault here is often with the customer not reading emails and snail mailings, but when it's widespread, then some of the blame has to go to Marriott for not designing a communication strategy with better results. "Bonvoyed"? Mostly not.
But Communication Issues also includes cases where Marriott never made the info available, like years of status prior to Aug 18, or what years were supposed to count ("proprietary"), or whether or when the sweeps have run, or how many dollars of spend you have, or how existing old travel package certs would be handled. All this info would be specific and actionable, and yet the program made decisions - explicitly or implicitly - not to share it with customers. "Bonvoyed"? Yup.