In the WarCraft 3 community they have a custom client and third-party ladder called W3Champions. It adds a few quality of life improvements like allowing you to not get matched against the same player again for 8 hours. But where it really shines is in the ability to moderate the community by banning bad actors. Some popular Twitch streamers tried out WC3 recently and in the official battle.net ladder they got players trolling them by making swastikas with towers or deliberately deboosting in order to snipe them. Once they switched to W3Champions the trolls all went away, but if any showed up they would get banned pretty quickly. One of the biggest benefits of building smaller communities is that it's actually possible to moderate them and elevate the gaming experience of everyone involved.

Another example is Apex Legends. Watching creators on Twitch and it's a massive quality of play (and stream) change going from random matchmaking and playing matches with a small selection of people.