What I don't really understand is why strings are constrained at all... why aren't they just lists of integers? Graham himself in essays has suggested exactly this and other functional languages use it.
I'm guessing that pg wrote it to use lists, but it turned out too slow (he has a site to run using arc), so he's using regular strings for the time being. The first thing you do when writing programs in a language like Haskell that munge large amounts of text, for instance, is to stop using the built-in strings-as-lists and switch to some sensible library like ByteString.
