Reading your post, one thing in particular caught my eye: the section where you say, “A notification when someone posts in their community”.

Personally, I think this would be a step forward that would boost interaction. I say this because, at present, to see the latest posts or what’s new in the communities to which, for example, in my case, I’m subscribed, I have to do so manually. And much of the content that might interest me or be worth commenting on is lost if I don’t look for it myself.

So that point about incorporating a notification system linked to subscribed communities would add value that would exponentially increase interaction between users.

It would be an excellent idea to recommend this improvement to the developers. Otherwise, the post has a very solid line of reasoning.