Queues on US servers are less active than usual as well. WoW itself is becoming less and less active. As a result, twinks are becoming less active. We need to continue to promote and advertise the 19 bracket in order to have a constant flow of new players joining to replace existing players that quit WoW.
There is a chance queues could be bugged/bottle-necked. Queues have been very slow in other brackets, including max level, as of late.
20-29 queues have been slow as well. I think queues may be bugging too, I got an instant pop while two of my buddies were in queue for an hour plus. All of us were heals, so I'm not entirely sure.