This is false. AV premades were nerfed twice. The first nerf removed the BG numbers in pop-ups and thus made opening new instances useless.
After this, however, premades found a new way: have a scout in a PuG vs PuG game, or in another premade, have him report when the game is about to end in 2 minutes, and report what BG number they were in. The premade would then queue into that specific BG number, and when the game would end, most of them would get in the same BG.
This way premades got 30+ people in, more consistently than with the old method. No extra empty lobbies were created. No alliance PuGs suffered any negative consequence now. The only affected PuGs were 5-10 PuGs every game who were carried to a win, and Iâve never seen one of them complain about it.
The second nerf had nothing to do about helping alliance. It was done purely to appease Horde, the dev pet faction.