With your team don't leave a dungeon (RDF) and then queue for AV. One team of my 10 man was doing a dungeon and left to do some AV (couldn't complete it). Well the team that didn't use RDF got queues twice (about 14 mins each) and my other team was at 30+ mins in the queue. After disbanding them and reforming I was able to get into AV. Appears to prevent you from really queueing.