With that logic, why not just provide an API. Everybody just hack together their own client. Being a hacker doesn't mean you never get to benefit from prior work, or never work together on something, or never share your work.
I get the appeal of providing a minimal service like HN, but unless I'm missing something, my proposed change is an absolute no-brainer considering it's effort-reward ratio.
The thought's occurred to me that among the conspicuous omissions from the HTML spec is of a threaded discussion (or more specifically, messages within a threaded context) as a first-order object, permitting arbitrary structuring of that content at the volition of the reader.
Though on reflection: if you're really interested in a technical discussion site, the speedbump of needing to code (or at least install) your own client might make for an interesting form of gating.
To that extent, your suggestion's somewhat growing on me.
I get the appeal of providing a minimal service like HN, but unless I'm missing something, my proposed change is an absolute no-brainer considering it's effort-reward ratio.