I guess this is Hitchens first encounter with such an idea, though you'd think if he were fairly well-versed in evolution this wouldn't come as some kind of epiphany. He dashed off an email to Richard Dawkins, and got this reply:
Vestigial eyes, for example, are clear evidence that these cave salamanders must have had ancestors who were different from them—had eyes, in this case. That is evolution. Why on earth would God create a salamander with vestiges of eyes? If he wanted to create blind salamanders, why not just create blind salamanders? Why give them dummy eyes that don't work and that look as though they were inherited from sighted ancestors? Maybe your point is a little different from this, in which case I don't think I have seen it written down before.
If Hitchens' point is that vestigial traits are evidence for evolution, then of course it's been written down...about a million times. I'm not sure what the heck Dawkins is talking about. If his point is different from this, I don't know what it is.
So as for being some kind of novel argument against creationism, I'm afraid it's as old as the debate itself. It's a good argument...but it's nowhere near new. And it's certainly not a silver bullet. Creationists can always give some version of "if god wanted to make a salamander with useless eyes, then that is what he did." This is on par with saying that the devil buried dinosaur bones, but its silliness doesn't keep people from employing it.