At level 80 random groups for Naxxramas, the 10 man instance, were running Naxx successfully days after the expansion has been released. Even for the heroic version of Naxx, the first 25 raid you might enter, are being run with success.
Now 2 german players solo'ed Loatheb, a boss in Naxx, in heroic mode! Thats how easy it has become.
The elite guilds hate it, casual players love it as the difficulty is ok for them. Two things start to happen: the elite guilds miss the challenge and casuals are raiding like the pro's have been before. Fun fun fun, but Blizzard has a problem. The pro guilds were the heros of WoW and casuals saw them as their role model. Of course they complained that they never can raid like they do, but still they liked that there is somethign after their level cap to reach, unlikely, but it is there.
Now everyone can raid and the feeling "there is somethign beyond" is missing. That might lead to the problem that pro guilds stop playing or waiting for the next expansion as there isn't an alternative for raiding outside WoW right now (neither WoW nor Lord of the Rings do it "right"). My personal opinion is that Blizzard needs to offer an elite content patch real soon otherwise they are going to loose the role models of the masses.
Check this: the majority of the playerbase never saw the inside of Sratholme before Burning Crusade came out, less than 5% of the players at that time never saw Naxx from the inside. Less than 5% of the playerbase before Wrath of the Lich king saw sunwell from the inside.
Yes, its the right move Blizzard to make things more casual and more fun for everyone, but do not forget what principle (among others) made WoW big: Elite content for the core players.