New Minecraft update lets Microsoft revoke multiplayer – even on private servers
minecraft.net
minecraft.net
Server unusable? - No, that's not how I'd describe our server. It was deemed usable by hundreds of players every day.
Griefers - you have the same problem in online mode anyways, many of the trolls have way more than 1 account. Use AuthMe for user authentication, use IP bans to ban repeat offenders, and most importantly - use anti-grief plugins like GriefPrevention.