Meta SE has various problems, and I believe that those problems need to be addressed before we try to attract more people to participate in Meta SE.
Jeff Atwood said almost 8 years ago: Listen to your community, but don't let them tell you what to do. We should expect SO Inc to listen to us, but we should not expect to dictate terms to them.
The network has grown enormously in those 8 years, and it appears that the Powers That Be no longer consider Meta SE to be an effective (or pleasant) way for the community and the company to communicate.
I tend to agree with that point. Part of the problem is that the Q&A format really doesn't work well on meta sites, and Meta SE has extra complications due to having its own rep. I feel that some kind of major structural change is required. One possibility is to replace (or supplement) the current (Q&A + comments) structure with a more conventional discussion forum, with proper threading.
Of course, a mere change of software won't make all the problems magically vanish, but I believe it would be a good start. With a new structure, hopefully we can build a place where staff aren't afraid to participate, and where the trust between the company and the community can slowly be rebuilt.