I miss Slashdot's 2-dimensional voting system, and meta-moderation system. It seemed to work fairly well, it's just that the submissions got stale over time and the community smaller which is all that matters in the end for this kind of site.
Ideal would be hn style sites, decentralized like forums, and managed by individual communities. Then, stick to a standard, unlike the old phpBB, vBulletin, etc, so there can be some level of access by API.
In my experience, the people in that community want to keep it small, and private. They don't want folks not like them, around.
A good way to ensure that happens, is treat anyone that raises issues about the way they are treated, like crap.
We won't stick around for abuse. The people that are gaming the system, will endure it as "cost of doing business," but the folks that want to get something from the community, won't stick around.
I hardly ever ask any questions, anymore, and have absolutely no interest in visiting, just to answer them.
At one time, I was quite enthusiastic about SO, but no more. The shine wore off that knob, long ago.
They got the community they wanted.