The soul of the game was faction war to begin with. Sure they could have made the game a non faction game with plenty of races to choose from with the ultimate goal each expansion being to defeat a villain but they didn't.
The point of the thread is the obvious imbalance in losing faction leadership. And since you mentioned Jaina she should have probably been killed off after the purging of Dalaran event but Blizzard had other plans for her since they make stories expansions in advance.