Its not the commenting I’m interested in. In fact, I have no real desire to have commenting on my wiki at all, except as a hidden kind of aside for discussing updates to a page, a la Wikipedia for example, where most people never see any comments.
I have no idea how much a plugin can do.
As far as I am concerned, for my purposes, a wiki is something that primarily displays structured information, that may be easily edited (either by everyone or by a set of registered users). Any comments should be at the least hidden initially, and I wouldn’t really care if there was no comments at all (some sort of attached “Talk” page would be fine by me). The other feature of wiki’s is the easy creation of new pages, and the automatic creation of URLs matching the names. None of that, to me, would work easily with Discourse unless plugins are fantastically powerful.
The things I particularly like about Discourse are the nice editor, the solid account system, with things like badges and trust levels, and the modern styling. But a wiki is a very different thing to a forum. I don’t know, maybe it’s possible to use Discourse with hidden or no comments (Replies), everything marked as wiki posts, etc. But the easy creation of pages and trivial linking would seem a challenge.
I had more hoped it was something that was on the agenda for the Discourse folks, but if its not, then I would potentially be interested in this.