I want to add this. Maybe, I am mistaken and Dungeon Finder tool works as intended. Some players tell me that if you use it as a tank or heal role, then you get a party in almost no time, but if you are a dps then it may take indefinite time.
Actually, I can not imagine how this could be true. Because, once a party is complete it should fall out from the queue list. And then other players move in, and it goes on a rotation.
But, if it is so and DF works correctly, then imo it needs an internal check for the time that dps players have to stay in a queue to finally see it proc.
Gonna check DF as a tank/heal role soon and post an update.