It all just returns to Blizzards biggest problem with it comes to the lore/atmosphere of the game, and that is that they can't find a way to make long lasting characters in the game stick compared to the amount of characters they kill.
Because of this, the game is getting more hollow as times goes on and the story of the game is being carried by fewer and fewer characters. The Horde is not the only faction who has this problem, just look at the Worgen and Gnomes. If their leaders die, the entire race has no apperant leadership.
Instead of making characters, that can stand on their own, who have their own story-lines and who does not serve the player as a servant, Blizzard burns their characters for short stories, where they end up as a "followers". Like the Worgen could have gotten alot by setting Crowley, his daughter and maybe other royals of the worgen up as individual characters, who interact with Greymane, but that is not the case.
For me, this action is a clear sign of two terrible scenarioes: Either Blizzard seriously do not know how to rebuild the complexity of their world(creating politics within races like with the Council of the Three Hammers) or they simply don't want to invest the time to make WoW last longer, only extending the overall story to a point, where they could end it quickly if it is needed.