https://wccftech.com/blizzard-estimates-hours-long-world-of-warcraft-classic-queues-contingency-plans-in-place-and-character-transfers-being-considered/

Blizzard is estimating severe World of Warcraft Classic queues up to several hours or more on the most popular servers once the game releases next week.

The WoW Classic Development team answered various questions during a Reddit AMA, and as expected, many questions were asked about the expected extreme queues on Classic’s servers. When asked about adding new servers when needed, Blizzard replied that contingency plans are in place to quickly open new realms but the team wants to match demand to avoid creating low-population realms. In addition, the development team also confirmed that they are considering opening up character transfers later on.