There are many comments of praise when we read that heroics will actually be heroics and progression will run like this:
Below is the basic progression map. Obviously your mileage may vary, i.e. If you're Paragon or Premonition you will be able to skip some of the below and/or mix and match at your discretion.
*Normal Dungeons/Crafting/Questing to get full set of 85 blues (non-heroic) to do Heroic dungeons.
*Heroic dungeons to get full set of 85 Heroic blues to do Normal mode raids.
*Normal raids to get full set of 85 epics (non-heroic) to do Heroic mode raids.
*Heroic Raids to get full set of 85 Heroic epics, which will presumably help a bit on Sinestra and the next tier (when released with patch 4.1.0)
*Badge vendors to help fill in gaps at all tier levels.
*No real gating to speak of for ship.
*Sinestra opens after Cho'gall is defeated on HEROIC mode. No timers or attempt limits, but she will pound you relentlessly. She has better than Heroic epic level gear (half a tier better).
Heroic blues? Players these days are inclined toward purples because, well, purple was blue as we end this expansion. Vendor gear isn't even blue and very easy to get. My lock had T9 before even setting foot in ToC.
Then you hear of people on test wiping (oh my!) on heroic 5 mans until they figured out the strat. And some actually liked the abuse.
And think back to the transition from BC to Wrath and the travesty that was Naxx. One long, winged trek that upper end guilds destroyed and was left to twiddle their thumbs.
The arguement is not casual verses hardcores now. I see it as veterans verses cadets. Especially for those of us who have played in vanilla (I rolled a priest because I heard druids couldn't heal end game), things being challeging and with a learning curve actually harkened back to a different era of MMO's. Everquest was still a juggernaut with it's insane camping and farming, mass key quests, and progression locks. Gamers these days were barely in Junior High when I started my first MMO (Ultima Online, in case you were wondering), and those of us who grew up and got lives certainly don't have the time or energy for a game with so many time sinks.
But we don't have to go back that far for a sense of challenge and awe. Burning Crusade, for all the boring asthetics and uninspiring bosses (more on that later), had some meat to it. I would even argue that Ulduar gave us that, too. I still shudder when I think of Heroic Mimiron! Then it seemed the crew jumped ship to work on Cataclysm and things kinda went downhill.
I for one am hoping that things stay somewhat difficult. But I don't envy the devs in their job to keep things difficult but still acessible.
One of my favorite things about Northrend was the fact that the villian was everywhere. The first dungeon for most of us was UK and BAM, Arthas is giving out orders and displaying his power. He's telporting here and there and reminding us, goading us if you will, that we are in his domain.
Even side NPCs like the various dragonflight including Chromie, the only gnome I like, made regular appearances.
Burning Crusade was very "meh" for danger. Every boss was locked away somewhere and I never got a sense of urgency like I did for Wrath. Mag was step in the right direction but would have been better if, say, Lady Vashj used a hologram to speak to a Naga chief in Zangarmarsh. I am sure there were better examples, but if there are, they didn't last long enough to instill any sort of emotion.
For those who don't care about lore, I am sure it's all meaningless. Some of us still like that immersion (again, another era) and feeling like we are part of a storyline speaks to an emotion commitment to a game.
I was worried that without such an iconic foe such as the Lich King, would I get the feeling of a real villain in Cata? One movie and an achievement won't make me a believer yet, but I do have high hopes that Deathwing and his army will make me feel inspired!