I can admit to being wrong. I thought the sharding technology used on BfA was done by continent, and it appears to have been in the early days of its use. I thought this would have to be changed to a per-zone basis if they were to live up to their “sharding in the early zones” word.
Now, it appears I had it backwards. It’s being changed to a continent or game-wide “layer” system and it may be used for longer than was originally implied. I was wrong; I’m sorry that this system is likely to extend further than I imagined it would.