OMG, I thought for a second you were talking about Discourse… 
Sorry false alert
As for the commenting system ( as mentioned here), I willing to bring my help.
Small issue I am a designer 
. But still willing to help ( planning, tutorial, design… )
The idea I had in mind was something similar to techcrunch.com commenting system, example:
https://techcrunch.com/2018/06/20/europe-takes-another-step-towards-copyright-pre-filters-for-user-generated-content/
First questions that come to my mind are:
- Should we use an api or web hooks ? Some kind of a plugin maybe ? Or even an iframe ( security risks ) ?
- What about registering new users ? Is there a way to connect/merge users with SSO for each CMS