World of Warcraft: Forever will avoid repeating WoW Classic's mistakes and will have tools to prevent "dead" or "unsustainable" server rulesets, Blizzard said. In the past, various WoW Classic servers became "dead" over time, as players either stopped playing or transferred to other servers. Those massive drops in population had major ramifications for players left on the server being unable to find groups for raids or dungeons, as well as for the server's economy and auction house. In some extreme cases, Blizzard gave away free character transfers so players could leave their "dead" servers behind.
Источник
GameSpot