I was able to play normally before 10am PST today, but logging on tonight WoW is flicking black on loading and game play screens. Tried a -compat game option from the previous thread’s fixes but no luck.
If you’re using a newer nvidia card, thinking 4k or 5k series, I’ve seen others post sucess rolling back drivers to February for various issues.
Not knowing your hardware, or what you have done already, here the support page regarding black screens.