It's all really the same. All bosses before Ulduar were "hard" at some point. Sure, people just went in and cleared the content, cause we had a preemptive strategy to work off of. All of the kind hearted players who ran the Naxxramas content in the "Vanilla WoW", and even the lucky few who ran through during The Burning Crusade, all knew what they were up against, and all had an idea of what was going to happen in there. So, when the time came in Wrath of the Lich King, people knew exactly what to do in these fights and situations, which were toned down slightly and revamped for 10 and 25 players, rather than the classic 40.
Ulduar, The new raid dungeon introduced in patch 3.1, is only hard for some, due to its "newness". As a collective, the players who were experiencing the endgame content in the initial installment of wrath, were asking for and craving a challenge that would take them time to complete. Blizzard's answer was Ulduar. With its release, people were rushing to the area to view the new dungeon, and Northrend and servers were crashing left and right. While some were able to clear and have content down the launch night, the world first Yogg-Saron kill, came to Ensida, only two days after the patch was released. People have questioned whether or not the guild had pushed themselves too far and too hard, or if they were coordinated and geared enough to do it without much error. Others complained that the content was far too hard to be completed even by classic "hardcore" raider standards.
Now in the recent patch of 3.1.1, there have been some noted changes in the fight, making it so that some mobs and adds that appear during a few of the boss fights can be snared and controlled, making it easier for some of the people to progress into. This falls under the list of bugs that are becoming less apparent, but they have fixed the issue with pets and minions not being able to attack Kologarm. Blizzard also hot fixed an issue with being able to sneak past some mobs leading up to the Mimiron fight, some argue that they are making the fights easier.
While the instance has been difficult for some players who can't PUG the raid, and some guilds have even disbanded over the difficulty and drama that result from the instance, some people are regretting that this instance may be "too hard". Comparing to some similar past events, this raid could be similar to the installment of The Black Temple or Sunwell Plateau raids, that were released some time ago during the end of The Burning Crusade. In the end, the initial intent by Blizzard with this new raid was to bring in a raid that would, "Amaze and blow people away" with its gear, graphics, design and challenges. This goal has been met.
Many guilds, and their management, are now gearing up, recruiting and retracing their steps through the old instances, collecting any missing gear, glyphs, and rethinking their actions and rotations with the new changes to many of the classes and abilities that Patch 3.1 has brought. Some who had relied heavily on the abilities and moves that they have grown used to over the past near five months since the release of patch 3.0, have dubbed this patch the "worst patch ever" and a ruiner of the game. While some have either left or are taking a break, their voices can still be heard on the official community forums, located on the World of Warcraft website.
So, a new question has risen with this insertion of "Hard" endgame content. Will this be the first and only time that Blizzard listens to the player base and inserts what is asked for, a "hard raid" that requires planning, training and strategies? Or will this be a harbinger of what is come in later patches. We have yet to fully get into the area of Icecrown, though with the introduction of the Argent Tournament, you are placed in the direct vicinity of the Icecrown Citadel in their later quests. I could not wait longer, and went around to ask some players what they thought of the new instance. The initial thought was that many players I spoke with are wondering "If Ulduar is this hard, what will the Citadel be like?" and "Will Blizzard make Arthas as bad, mean and tough as the lore and story makes him out to be?" Over time, we will tell.