From a technical point of view, I’d rather Lemmy didn’t federate except with itself, and maybe possibly also with similar networks, but only as long as that doesn’t hold Lemmy back from doing its own thing.
Getting ActivityPub federation to work reliably between Lemmy instances alone is already proving challenging for developers.
From a personal point of view, I have zero interest in what I consider a shit paradigm of social communication. The “micro” lie in micro-blogging, as you quickly conceded, is long gone. The interface is horrible for effective exchange of well-thought ideas. The social networks formed are hypernormalized echo chambers of unhinged ranting faux intellectuals and champagne activists, usually led by a cult of personality or two who are tasked with making sure the one-upping posturing game continues forever.
When you are about to "micro"blog, presumably you will be writing something coherent enough that it relates to a certain subject of interest to a section of the public. It is also presumably meant to be viewable by the public since you’re not sharing it in a private group chat.
If that’s the case, there should be a community in Lemmy where those interested in that subject congregate. That community would either be low-traffic, then you can make your "micro"blog a post there breathing more live into it. Or it would be a high-traffic one, in that case a lounge/chat/MegaThread post should exist where you can chat with people interested in that subject, in an interface that actually facilitates good discussion.
https://github.com/LemmyNet/lemmy/issues/3827