For what it's worth, as someone participating in communities I'm likely to gravitate toward the most established one irrespective of what instance it's on. If there's a problem with an established community (bad moderation policies, bad moderators, lots of posts I don't like, or whatever) then I'll look for alternatives.
But generally, I'm more interested in more communities covering new and niche topics than I am in local copies of communities that are healthy on another instance.
I see what you mean but that would require you to make an account for each topic you want to discuss. If they make it so you can have one account for every instance that might be great, though
Ya know, seeing both terms next to each other like that, I realized: if we were to call Lemmy communities "sublemmies", not only would it be great in repetition, and it definitely has a nice smooth ring to it, but we'd also get to refer to things that happen in them as "sublemminal". 🤓🤘🏼