My understanding was that WoW would do essentially what's described here for the player's character and entities in the immediate area (simulate them for the next few frames), but the server also maintained a view of the world. The client would occasionally sync with the server, and that's when you would see the blinks.

If you're curious, this[0] is an actively maintained implementation of a WoW server.

[0] https://github.com/mangoszero/server