A notification mute or "unfollow" for discussions we've stopped caring about should really be an option. I seem to constantly have new notifications telling me that a discussion I was a part of, but am no longer interested in, is still going on, with "xxx and yy others commented in..." and frankly, it's a little silly. Most discussions do die out, and it eventually goes away. However, even then, particularly in the case of pinned posts, you're get a re-drop and all of a sudden, a new wave of activity, and the resultant notifications appear.
I'm not talking about the entire product discussion, though being able to opt out of all of it, or all but MD/Rep notices might be an interesting option, but rather these reply chain sub-discussions. I like knowing if someone replied to certain topics without replying directly to me, but others, the discussion is overly active, and notifications are pretty constant. Quotes and mentions are justified enough for new notices, but new notifications for something that has had dozens of replies, with none of them mine, not even a check on what's being discussed, is mildly annoying and as of now, I'm not seeing any way around it.
I can live without it, obviously, but being able to do something along these lines seems like something most people that actually use the discussions would find at least somewhat useful.