I'd rather not introduce Yet Another Place (we've already got these forums, IRC chat, and github) to talk about bitcoin development.
These two statements contradict each other, because github is Yet Another Place, too.
I do not see any point in moving the discussion of
some bitcoin changes to a special place outside the forum. Discuss changes on the forum just like we've always done, regardless of whether that change is a proposal, a patch, or a pull request.
The forum is perfectly adequate for discussions.