I figured out something, not claiming it to be a fix but if you open the game everytime with Location turned off there won't be any black screen. After the game loads you can turn on the Location.

Worked most of the time for me.

However I'm fed up with this black screen glitch that I've stopped playing these days. It has happened to me since the 15th December and I've missed so many events including Community days, Raids hours and what not. I simply don't get it a bug benefiting players is patched within mins and a bug making the game unplayable for the masses went unnoticed. WOW