That really also deepens on the server you are playing. I have 2 chars on a PVE realm (alliance) and I can tell you I would need 1 year to lvl up as we loosing against horde almost every fight. And that in all Bgs even in WSG where usually Ally is ruling :-) I have tried to lvl trough pvp on another server but I didn’t succeed I still needed to do pve, otherwise it would have taken double time.
You necroposted for some really bad info there.
What server you're on has no effect on BGs anymore. At all. Unless you want to bring in US vs EU, which will have an effect.