Maybe I'm just misinterpreting the previous comments on this article (which I found fantastic, might I add), but I'm almost convinced this darker development in The Office's presentation as a comedy is a GOOD thing for the show. Frankly, I felt seasons 4 and 5 were major slump seasons; they were starting to run out of good gags and since the only constant subplot in the entire series, Jim and Pam, was coming to the climax we've all been expecting since Casino Night (if not before), the series needed a transfusion, and badly.
I think what the writers have found in the season is just the transfusion it needed. No longer do I consider it one of the funniest shows on television, nor do I think it's really all that funny anymore, but there's something deeper lurking in the writing that makes it still one of the best shows I watch on a week to week basis. And that's because I feel the writers have realized they have run out of gags, and now have to focus on the only thing they've got left (and a strong attribute it is): the characters. The Office, I've always thought, has had fantastically well-developed, fleshed out characters for a standard network sitcom and this season's darker approach has been EXACTLY what I've been waiting for since midway through season 4.
Don't get me wrong, I think the show is getting tired, and I don't think it's got anywhere else to go past, maybe, season 7, but I'm of the opinion this is the best season (in terms of television quality, certainly not laughs) since season 3.