No, I'm not sure. But from a quick look, it seems like most GET handlers on HN take at most two parameters, except for "flag" which takes three. The POST handlers take more, but that's stuff that needs to be sent to the user anyway, because the user is editing it.
Out of the stuff that I did see, the "goto" parameter is the most obvious candidate for the closure treatment. It's also the most obvious candidate for the AJAX treatment, if you add in-place editing like on Reddit, which would be a better UI in my opinion.
Sorry if that sounds arrogant! Of course there could be a lot of functionality that I've missed.
> There's just not that much state to be preserved
Are you sure? From my perspective there's enough to make the complexity difference in the two models significant.