>>hn_thr+(OP)
If the moderators kept everything else the same but bifurcated into hn-tech and hn-polisci you might think it would work.
But hn-tech would have a strong tendency to want hn-vi and hn-vim and hn-emacs, and hn-polisci would want -left and -right and -libertarian and before you know it, you've made reddit.
Reductionist, but I suspect you'd break the golden goose.