He interviews various casual raid guild leaders in his piece. These are guild leaders who, back in Burning Crusade, mostly ran Karazhan and maybe dabbled a bit in Zul'aman. They certainly were far behind the curve. But they had a dedicated core of 10 raiders who got together, faced the challenges, and overcame them. But now, even these casuals are saying that the end-game is just too easy.
One guild leader interviewed is finding that some of their raiders have gotten all the loot they need from Naxxramas and maxed out Northrend Achievements and Reputations, and, for lack of anything to do, are not logging on for days or simply letting their subscriptions lapse altogether, leaving their guild leader to make the painful decision once Ulduar comes to either refuse to give them their raid slots back or kick out their replacements.
Another guild leader is just beginning Naxxramas, but whereas in BC there was a sense of excitement and challenge at starting Karazhan and Zul'aman, the guild leader says now that Naxxramas fills a bit like a glorified PuG, one more dungeon you run for badges and loot, rather than an epic challenge like BC-era raids.
Karthis ends by insisting that Ulduar won't solve any problems. "Hard Mode" doesn't really create any new content. Most guilds won't try the Hard Mode, and the few that will will still burn out on running the same content over and over again, even if they can bump up the difficulty on certain fights.
Of course, these stories are anecdotal, so it's hard to say how true they are overall. Still it's thought provoking all the same, especially to hear traditionally "hardcore" complaints coming from casual guilds. I'm still pretty in love with Wrath, but I know I'm quickly running out of things to do and finding myself hoping 3.1 has more content than just Ulduar to keep me busy. I also have to wonder if simply dressing the same encounter in a new set of clothes by insisting raids deliberately handicap themselves or fight counter-intuitively and calling it "hard mode" will really keep anyone's interest in the long run.
The comments on the blog actually bring up good points as well. One commenter believes that 2.4 actually put dungeon accessibility where it needed to be by removing attunements and creating badge and craftable gear that was just below raid power level. They just started too late, then overcompensated in Wrath by lowering difficulty too much.
It seems like the argument comes down to a few basic questions: Is the End-Game too easy? Is there too little content? And finally, are "hard mode" achievements with better loot a valid end-game mechanic, or simply a way to mask the fact that the end-game content is too easy and too sparse?