Effectively, because of the way games are formed, this queue is unworkable with less than 20-30 people in the queue.
If everybody is solo (or at least small groups) everything chugs along randomly putting people together and there’s at least a shot at a good match now and then. PUG groups break up and reform enough that even with the silly continuous queue (which was a bad idea) there is enough churn to make the queue healthy.
This stops whenever the first (or second) 5-man enters the queue. Because they have an instant full team, they jump the line and get paired with the first waiting solo group. This means that even when there are two 5-mans, they have little chance to play each other and will usually be repetitively paired with solo PUG groups until they manage to scare off enough of them that only the 5-mans are left. (And if there’s one of them…well the queue dies completely).
Please do something about this before going F2P (or whatever) or you will just shoot yourself in the foot. One queue is just an instant death spiral and the community of this game does not police itself at all. The solo/duo queue should at least be put up most of the time unless you can modify the queues to prevent obviously bad matchups…