Dear Administration,
Why wouldn't you make the server temporarily PVE?
This will stop ganking and any PVP-disturbance while leveling. And I think this will raise the Alliance population up, opening for them most popular areas for leveling (like STV, Tanaris, Ungoro which are taken by Horde now).
Closing the creation of Horde characters is good decision, but it will not stop ganking. The problem is that many Alliance players can't level up being killed every time. Even if you disable creation of Horde, the "old" Horde characters will be still on their way.
Someone may say, that PVE server will make an ore/herb farming unreal, because players won't be able to kill their farming opponent. Just raise up the resp rates of ores & herbs. For example, make the ore resp at once after it was gathered. The server is overpopulated and this resp rates will help everyone to level up their professions.
P.S. Don't disable racials plz, it will be the undeserved punishment for all players.