As solo-queue only on Horde, I'd say I see around 1/3 of the games with 4+ group queue twinks from Alliance. It feels like those same games have the least geared Horde in them too. The other 2/3 of the games are winnable, the balance shifts back and forth.
Statistically, I'm at 44% wins (If I exclude the group queue Alliance I'm around 66%). I think I've been in maybe 5% games where Horde were farming at an Ally GY... BUT since I have an Ally 20 also, I know it occurs, I am just not in those groups.
And, I think I've only ever seen 1 game where it was group queue twinks vs group queue twinks... So I think the problem is more around the matchmaking pools... no one wants to be in queue for 1 hour while they we get enough group queued twinks.