I think voting is a helpful first pass filter to cut down on the noise, but it needs to be capped or it becomes a game. I think Slashdot made the right call by capping the votes to +5/-2 and being somewhat stingy with their voting points. They also don't allow you to post and vote on the same article.
Any discussion system that wants to grow large and doesn't have a plan to deal with trolls is doomed to fail. It would be like building an airplane but not taking wind resistance into account.
Building something like this would definitely boost user engagement, which is something we've talked about wanting to do. I just worry that it could turn Pairagraph into something adversarial. At its best, we believe Pairagraph is a place for exploratory conversation rather than debate.
It might be interesting to allow readers to vote on who they'd like to hear from in the future... Maybe that's a way to maintain a high level of dialogue quality while still allowing users to have a say about who and what is discussed on the site. What do you think about that?
To increase user engagement, what about allowing users to carry out threaded discussions of their own in a part of the UI that is distinct from the main conversation?
Perhaps users should have to opt-in to seeing comments from the "crowd", and there should be a minimum amount of time the user has spent on the site (and discussions read) before they can comment. Also they'd have to receive a minimum number of upvotes for their comments before they were allowed to vote, etc. which would gamify it a bit.
Rather than fighting the echo chambers, you could use them to your advantage, by requiring users to pick a side they support in each topic and splitting the discussions into two camps. That way expert A could see popular comments in support of their position, and expert B could see comments which support them instead. They could even opt to see what the other camp was discussing, to make sure they weren't misapprehending the other side's position.
My other request is that you make the site work without JavaScript. People don't want your annoying pop-ups, and it should be possible to present text in a browser without running scripts. (Also it might be nice to have meaningful URLs, like Reddit has).
I think Medium's "highlight" feature is one of the things that they did really well, allowing readers to bring attention to those sections which were most impactful.