It has been mismanaged. Seriously mismanaged and neglected. I could generate quite the laundry list. But instead, I'll just point out that Hitchens gets out of his fray what he puts into it. Which is zilch. I'm not sure, but I doubt he's ever posted in it. In fact, it's sooo beneath him, that he went through the extra effort to assign the task of posting to a lackey when the occasion warranted (m=18104625). That said, all the best commentary abandoned his fray when the fray editor(s) decided to ignore it, and instead reward the ad hominem artists.
Even so, I bet that in the days following a Hitchens' piece you could, if you tried, find good substantive criticism in fighting words. But you first have to dissuade yourself (and I'm speaking of Slate here) of the reflexive and convenient belief that the fray is a sewer.
My sense is the internet presents old school journalists and columnists with a real challenge they resent. They took the right classes and college, they made the acquaintance of the right people and they've done their time in the trenches. In short, they feel they've earned their place as members of the media. In the good old days, that would be that. But with the internet, their worth, their due, is being challenged. The collective efforts of a writer and editor(s) simply aren't a match for the thousands of people who now have the power to bring their intellect and expertise to bear in direct relation to a writer's hard work.
There is currently a good example of this. Gregg Easterbrook's latest, In Search of the Cause of Autism sounds reasonable enough to the inexpert ear, but is in fact exceptionally embarrassing if you bother to read the comments made in reply to it in the science fray. There, actual scientists have taken the time to vet Easterbrook's foray into science and have found him not only wanting, but plainly wrong. But that's not just a commentary on Easterbrook, it's a commentary on his editors as well. And that is a commentary on the print journalism model that these professionals are trying to apply to internet journalism. It doesn't work, because no matter how well researched and fact checked a piece, there are going to be experts who know the material eminently better than the writers and editors, and those experts are now empowered to expose these pieces as flawed with a few key strokes and clicks of a mouse.
The long and short of it is what used to be good enough no longer is. Journalists and columnists now have to suffer the scrutiny of the collective intelligence of everyone with a computer, and the best efforts of well established print media writers and editors are being called into question by that collective intelligence. What used to be good enough isn't good enough anymore. And that is the cause of much resentment among those professionals. And that is why the fray here at Slate is not only neglected, but subconsciously sabotaged in such a way that it can be easily dismissed.
Update: If there was ever an article that would benefit from appends, Easterbrook's is it. The fact that there seems to be a new policy of no appends only serves to bolster my case for the besieged mindset that is crippling the editors and writers at Slate.