One thing comes to mind with the WoD launch:
The two quests leading to the establishment of the Garrison. One was to mark the trees, and the other to kill a few birds, became a huge bottleneck that broke. Players ahead of that point were ok, but the rest of us (at least on my realm) came to a grinding halt that took several hours to resolve.
My wife was one of the lucky few, with only a few minutes separating our progress but I was caught in it.
Reflecting back, there was a stream of characters progressing through, like the mid to back runners of a marathon, at launch. Same as Pandaria.
Although I felt the Dragonflight’s choice of a boat (what could possibly go wrong?) proved to be problematic, and for me the World Server dropped out early on while I was logging in and out of alts to get them ticking, knocking me off for an hour, I didn’t notice the same phenomena once we got past the boat.
I saw people here and there but not what I was expecting, and the rest of my launch day was enjoyable.
