Writing addons for XenForo we have to deal with comments very often. Comments for pictures, events and other entities. So I have an passion to write the separate commenting module that can be associated with any entity. It will allow to unify all the comments in many different addons.
It will look just like profile post. Comments will keep content_type and content_id of associated entity like each Handler does.
So I'm interest the developer's opinion. Are you ready to integrate such thing with your addons? Of course if it will be easy to use and well coded.