In case anybody hasn't noticed. There are three important things.
The first is which, that Ensidia, the guild that was responsible for the original first 25 man kill of the Lich King, was (all 25 people that participated) put on a 72 hour suspension and had their title/achievement removed due to a very odd bug making a grenade have a chance at rebuilding parts of the floor, making the encounter much easier. Weather or not it was exploited or not, it no longer matters because Blizzard took action. Paragon holds the "World first 25 normal" kill now.
This is just a brief explanation of what happened, you might want to check their website for any more of that information. Moving on...
The second of which, for those former World of Warcraft players who are surprised at how much of a short time the Lick King was taken down and other people who try to downplay the boss as an easy disappointment. Things have changed drastically since Original and Burning Crusade.
The biggest that you will notice is that all classes provide some sort of group benefits, and some classes have similar benefits to make sure that class stacking is not a necessity (For example, Retribution Paladins and Survival Hunters both can provide 0.5% mana regeneration when performing their attacks. this make it so that class/specs are not an ABSOLUTE REQUIREMENT, aside from y'know, the essentials like healing and tanking.)
Not to mention no 40 man content, the thought of assembling 39 people on time for a video game seems like a nightmare.
The other is that gear is now easily, MUCH more accessible in this expansion than ever before. Some might argue that it worsens the game, because gear was the standard in which you were judged. And it is true, there are some horrible players out there, that now have easy access to powerful gear that they use poorly unless they improve. But what needs to be understood that in ALL games, competitive, single-player, Turn based, there are alot of shitty players.
Other than that, because gear is accessible to people who WANT it, instead of toiling for months on end playing the game of chance. Gear, the definition of power, is available to anyone, and with power grants your player the opportunity to band together and kill a 7 year old character fallen paladin turned mass murderer turned undead demigod.
And being able to get gear to do those things now, is much better than going through 5 different raids IN ORDER just to gear 1-3 out of 25.
Holy shit that was a long post.
EDIT: Oh and another thing, The Lich King has 17 million health in 10 man, and 78 million in 25 man, and that's not including the lackeys. Your raid has to be consistent, and at the same time, deal with the curveballs he throws at you. The video showing the entire encounter is a total is 18 MINUTES long, which is one of the longest fights the game has ever made. This is no 6 minute boss.