You could maybe achieve that with this design if a summary could be set for resolved discussions and shown at a higher level (eg. when hovering over the source text of a thread).

Having the ability to differentiate between a resolved, useful thread and a resolved but ultimately unnecessary thread might also help avoid noise.

Yeah exactly, it would be interesting to see a concept where the center piece is a consensus document where you could hide/show sections that are more or less controversial. Instead of leaving comments you propose changes, sort of wiki style. But to facilitate a higher level of difference of opinion, changes should have some mechanism for validation against consensus. And controversial changes should not be discarded but instead folded away in a linked comment-like.

Then there also needs to be a mechanism for working towards succinctness.

Interesting, will explore more.