Only way for that problem to be solved is to actually make the server blizzlike, by making the glad title only to be obtainable trough 3v3 games and not 2v2. As for the rated battlegrounds, people actually enjoy making premades and running in randoms to roflstomp the newbs and boost their egos. Be that as it may you can't really stop them, there's no way to prevent people from queuing, what you can do is to make the rated BGs necessary part of the game, as you proposed. But to ultimately make the game a bit more balanced it would be smart to make it so the random BGs don't give conquest points. So it will be a place for new players to come in and get their honor gear, after which they can step onto the next stage of pvp, and obtain the rest of their gear trough arena and rated bgs.
Of course these are just the ideas.