Closest would actually not be Twitter but the /comments after a subreddit. There used to be a tab for it, but they've hidden it. It's just basically all comments posted in a sub.
Granted microblog is just all comments in that microblog area but it's the closest thing to it.
I still think it's needed but it doesn't need to be forced. The /m/technology can have a "local" and "federated" tag so the users can pick and choose whether to see Kbin or the rest of the lemmyverse magazines/communities.
One other problem is that people won't be bothered to know the name of the site just the community. Like on reddit, it's just /r/technology and /r/askreddit. On Lemmy, it's beehaw/c/technology and then some other one which I don't remember which is a problem.
/m/asklemmy should just go to all of them and then I can pick and choose which ones to see.