Easy solution would be to have either a dev blog or a dev twitter where they can post small updates, e.g. “We’re doing some class tuning, watch for a minor patch later this month” or “old raid difficulty is on our radar and we’re working on it.”
Telling the community that they’re aware of and addressing a problem would calm a lot of tempers. Blizzard’s corporate culture is very headstrong, and as of late they’ve been especially bad at communicating. As a result, a lot of people are easily frustrated with Blizzard; WoW players invest a lot of time in this game, so the uncertainty about what’s coming next causes tempers to flare. For Blizzard, improving their rapport with customers would go a long way to soothing toxicity.