> * Run on hardware an order of magnitude more powerful than was available to the original WoW server devs, meaning that much simpler solutions with far less sharding / IPC / configuration can still scale sufficiently well

well the hardware was never a problem, but the user base.

you can basically run a 100 people reverse engineed wow server on basically a server with 2gb-4gb memory and a non virtualized cpu (a older gen one, dual core probably enough) and you would more run into networking limits than in actually performance issues.

the problem with wow classic/burning crusade/wrath of the lich king, was mostly the overwhelming people, servers took way more than 100 people, and the biggest problem was logging them in, if there was a prime day, all sharded servers could login too many people which overloaded login servers quite regulary.