I'd like to see more instances with 100-500 users.
I know that's a community thing, more than a Lemmy thing. I just don't feel like I have a wealth of choices. I'm still on lemmy.world and when I look around, I don't see a lot of medium-sized instances to migrate to.
Try to join an instance that is related to your geographical location or your country or state. That should result in a more even spread than what we have right now.
It's a lot of work to admin an instance, though. I can understand if random people don't want to do it. I hope one day someone does, because a California or Socal instance was the first one I looked for, too.