Horde population on Blackrock is tiny. It is like 1/5 or 1/10 of allies.

Finding teammates to play with is a problem for many on that side. On non-peak times ive often checked and there are only 40-50 players online. As a horde player there is huge pressure to switch side. Ive seen people spam global for a teammate for a few weeks and just give up and roll ally.

Allowing crossfaction arena teams would increase the pool of potential people to play with tenfold for hordies and by like 10% for allies(hue). I think it would be a gamechanger for horde and would make Blackrock more fun and a better place.