That is a problem yes, but this is a discussion about PvP, where racial imbalance is a much larger issue. Its flat out killing any PvP because PvP relies on both sides have stable populations and is a much more competitive environment. Should Horde racials be balanced in respect to PvE? Absolutly. Is Horde being better at PvE as big an issue and as detrimental to the game as Alliance being better at PvP? Hell no. Alliance being better at PvP prevents people from getting into it, it prevents world pvp, it kills competition, and the races that are overpowered are so overpowered that you're absolutely forced to play specific races, and for the entirety of the season.
It did nothing of the sort. Horde was better for PvE, Alliance for PvP. Horde was made lesser for PvE (good) Alliance was made way better for PvP (bad)