HN could be done without anything other than what the OP suggested.
It would work a little bit different (there would be a few more refreshes, for instance, on voting) but for the most part you would hardly know the difference.
It actually was. The current version no longer does this but the first one did. Which is kind of neat: under the hood HN has been almost completely revamped but it still looks almost to the pixel the same as the first version.
