Lead Systems Designer Greg "Ghostcrawler" Street posted an entry on his blog yesterday called "Wow, Dungeons are Hard!" It's a rather lengthy (but worthwhile) read about the current state of Cataclysm heroics, Blizzard's philosophy on designing them, his impressions on their current difficulty level, and some advice for improving your performance.
Like I said, it's an epic post, and we won't reprint the whole thing here. This, however, is the key takeaway:
Wow, Dungeons are Hard!
The bottom line is that we want Heroics and raids to be challenging, and that is particularly true now while the content is new and characters are still collecting gear. They're only going to get easier from here on out. We want players to approach an encounter, especially a Heroic encounter, as a puzzle to be solved. We want groups to communicate and strategize. And by extension, we want you to celebrate when you win instead of it being a foregone conclusion.
On the other hand, we don't want you to stumble your way to victory. We don't want you to be able to overwhelm bosses without noticing or caring what they're doing. We don't want healers to be able to make up for all of the mistakes on the part of the other players. While at the end of the day, dungeons may just be gussied up loot vending machines, we want you to do more than push a button to get the loot.
Ultimately, we don't want to give undergeared or unorganized groups a near guaranteed chance of success, because then the content will feel absolutely trivial for players in appropriate gear who communicate, cooperate, and strategize.
All that being said, though, is Blizzard really satisfied with its dungeon designs and their current level of difficulty? Hard heroics are indeed hard, but the updated PTR patch notes for 4.0.6
(which went live just yesterday at almost the exact same time Ghostcrawler was discussing heroics) indicate that a series of nerfs is coming our way. That will no doubt lead to player rejoicing, but remember -- heroics are naturally getting easier as people get more familiar with them and players continue to compile better gear, which makes completion even easier still.