One source of frustration for World of Warcraft adventurers with the Cataclysm expansion was the difficulty of its dungeon content, which Blizzard acknowledge as a weakness on their part.

It's because they were "primarily designed" before the Looking For Dungeon tool kicked in, meaning they catered to guilds with players who knew one another, and thus how to work together.

World of Warcraft's second expansion the Wrath of the Lich King introduced phasing to the MMO community, where an area of the game world altered to reflect major story elements.

While it helped to make Azeroth feel more immersive, it also cut players off from one another. Mists of Pandaria will have less phasing, and keeps everyone in sight.