Honestly I wish there were less communities. I've said this before, but people treat Lemmy like late-stage Reddit, expecting niche communities for everything, and we end up with hundreds of communities with no (or one, if we're lucky) active members.
This problem is then amplified by the fact that these niche communities are split even further across several instances, so our userbase ends up completely dissipated.
I would love to see users focus on a smaller number of more general-purpose communities. Of course, these should still be shared across instances, but I think we would benefit a lot from having, say, a "video games" community instead of 500 specific game communities.
As a side note as well, I don't think we shouldn't be "allowed" to create more niche communities (though if an instance admin wanted to regulate, that's their call). I think this should be more of a user culture shift, if anything.