They’ve said they’re going to use sharding as a solution for the launch rush. They haven’t given any specifics about exactly what that means (zones, time period, etc.). They likely won’t because they’ll probably want to retain some flexibility to deal with the launch without having 1,000 daily threads on the forums about how they promised this or that. However, they have said multiple times that they understand that permanent Sharding is not what the community wants and is not something that belongs in Classic.