The more organized it gets the closer it will come to 7 healers vs7 healers. This way you have to settle for a simpler, faster strategy and shortens queue time. It is incredibly annoying when people won't talk and their are times when your team simply won't listen so you just can't win.
There is luck involved but skill in organizing your team becomes a factor. You may call it luck, but I managed to win 59/70 dungeons I attended this event. The way the classes are, there isn't much room for skill outside of team organization and strategy, so I really like the mix of players.