Video contains spoilers of dungeons in Cataclysm.
The video you see here is Heroic Blackrock Caverns, as described/discussed by TotalBiscuit from http://www.cynicalbrit.com/. As you can see, it looks fairly difficult, as do many of the heroic versions of instances that we have seen so far from beta testers. But is this a bad thing?
Granted, once people start attempting to hit up heroics in Cataclysm, there will be waves upon waves of complaints about the difficulty of the instances (I've heard the complaints have already begun from beta testers but hey). I pray that Blizzard refrains from nerfing the fights too harshly, because it's stuff like that that helps players find out where exactly they stand skill-wise, and what they should do to improve themselves so that they are playing at the level of the game rather than depending on gear to play for them.
But what does this all have to do with the social aspect of WoW?