After the victory on Draenor, Thrall takes Grommash with him to Orgrimmar. Even though the rest of the Horde seems skeptical, Thrall insists. After a while, the other Horde leaders get together and come to the conclusion, that every bad thing that happened over the last years, to them and to the rest of the world, was because of the orcs, and that they would be better off without them. They decide to meet with the Alliance leaders, and together, they begin the unorcening of this world.
New class: Orcslayer - one shots every orc player
Main villains: Thrall and Grommash
There are no new zones or dungeons, but every orc NPC will be removed from current zones and dungeons.
There will be one raid, and it's called Orcenhold. It is full of orcs that are tied to poles, unable to attack. The endboss fight is a fight against Thrall and Grommash. Grom charges the players and immediately dies. Thrall breaks down sobbing, and holds Grom in his arms, while players shoot Thrall in the head.
After the raid, every orc player character will be deleted, and orc character creation will be disabled.
While the players skullfuck Thrall and Grom, Nozdormu comes down and seals this timeline, to make sure no more orcs exist, or will ever exist, or will ever have existed, in any timeline.
The Forsaken turn back into humans. The Blood Elves and High Elves still live together happily in Silvermoon. The human kingdoms are all still intact. The gilneans never turn into Worgen.
The Alliance and Horde never go to war, and everyone lives happily, to the end of their days.
The end.