Nostalrius Begins - Quality wow vanilla realm (1.12)

disable the smooth shaders option in your video options menu. this mostly has issues with the later graphics cards and blizzard during vanilla did not update this until later on.

after disabling the smooth shaders and reloading the wow client. thunderfury will be blue and purty.

Also works to delete your WDB folder - then you have 'em smooth shaders

Actually, I resolved the "black thunderfury skin" by moving to another 1.12 wow client.

(I heard some client were corrupted)

Switchblade, that's a luxury us peasants on slow internet doesn't have.
Takes like 1,5 hour for me to download another client