To me, the article seemed to be not so much a general criticism of the Potter franchise so much as a lament for the state of literacy. He also seemed to have his guns aimed at the nature of book marketing.
To be fair, I highly doubt there's all that many Potter fans out there who consider the entire phenomenon to be in any way artistic or enlightening. At least I hope there isn't. In fact, amongst adult fans (and I count myself in this number), the attitude towards these books seems to be that they're a guilty pleasure.
And if I may be so bold as to criticize a seemly intelligent (and quite naturally well read) book critic, I don't think someone should bring up such things as writing with a "wit-free tone" in an article peppered with an abundance of lame, Potter related metaphors.
Having said all that, I'm just a guy who enjoyed those books, so I may have a bit of a bias. Despite the fact that, as the writer shows, this so-called Potter-mania has not encouraged more reading, I still think it's a superior alternative to fixing one's self in front of the TV.