The Dungeon Finder in particular has really opened the doors of dungeons for players in many positive ways. That said, of course there are some shortcomings. We can't always put up design road blocks with the worst player behavior in mind, because that type of behavior is not the norm and shouldn't impede features which provide useful functionality for everyone.
We will continue to look for ways to improve the system to prevent abuse and griefing though, and we do welcome your feedback. :)