Yes But I am looking at a different idea. As we can embed a discourse topic as comments in another site. In theory we should be able to embed a topic as comments in a discourse topic. With maybe just using a theme component maybe.
I have completed a staruc iframe test. It works - however it embeds the whole site with header and footer in my case in mobile the f have component.
So My thought is maybe the embed js code might be able to be adapted with a tailored iframe added to a topic as comments on final post in a topic.
Benefit potentially no plugin required expanding usability to any discourse site via simple TC. Well maybe not that simple. 
The other benefit over journal and post voting is that a member could goto to the full comment topic or just view from Article topic
Though a Plugin could likely have some overrides for a special comment category to restrict post/comment length and other goodies But maybe not needed.
I should have maybe clarified in the Op that I am aware of both Journal plugin & post voting.