I have tried Drainor and Stormscale (Hord/Alliance) and as soon as I pass 45 on both servers BG wait time jumps to over 30 minutes! Any suggestions server/faction wise? I level via BG's while doing PvE dungeons once.
Battlegroups are merged, the server you play on will have no impact on how long the queue will be. Alliance in general has shorter battleground queues than Horde however they also have a lower win rate for all non 40man battlegrounds.