I think there should be a toggle option, similar to the "Join a dungeon in progress", which enables folks to choose to toggle whether they wish to be paired with first-timers. That way, the impatient players have their own place to grind (even though, really, it would be faster to go into PF and build a myth grinding party that way), and first-timers and folks willing to help (like myself) can be paired together to clear content without having to worry about rude players.