I think you're painting Blizzard's decisions with an unfairly critical brush here. I doubt Blizzard made Horde racials OP just to fuck over Alliance in the long run. Much like the Fire Mage Mastery stacking in 8.3, it was an unintended side effect that they couldn't just press an undo button on after it happened. An argument can be made that they waited too long and the damage had already been done by the time they began to reign in racials again -- this is fair criticism -- but it's still a bit outlandish to say that Blizzard "let" the situation spiral out of control due to complete apathy on their part.