"Why not make this thing easier for normal people to figure out?"
For me, at least, the value of Qoura is that normal people haven't figured it out yet. Once Eternal September hits I suspect I'll slowly lose interest as noise drowns out the signal (c.f. Slashdot, Reddit, Stackoverflow, ...)
From Quora's perspective, that puts them on the path to being the next Friendfeed -- not a good outcome for the investors who valued them at $86M last spring.
HN is pretty easy to figure out and thanks to Techcrunch et al has had ample opportunity to be overrun with junk. So it can be done. In fact it should be easier because here we all share a front page, but Quora can use the social graph to massage results.
HN doesn't have to exit at a multiple of $86 million to generate returns for investors and so can afford to be a niche site carefully curated to be uninteresting to the mass market.
For me, at least, the value of Qoura is that normal people haven't figured it out yet. Once Eternal September hits I suspect I'll slowly lose interest as noise drowns out the signal (c.f. Slashdot, Reddit, Stackoverflow, ...)