Currently, Ghost provides the ability to hide comments in the comment feature on posts. However, while hiding comments is powerful in itself, there isn’t really any other form of moderation feature.
Given this, I would suggest addition of the ability to indefinitely or temporarily ban a member from posting comments, with a reason able to be specified which is displayed when attempting to comment, and likely also an email to the user upon being banned.
I feel like this would complement the existing feature well, and would allow for more targeted responses to consistent bad faith actors, or particularly egregious comments. I would also imagine this would likely work better if a moderation tab existed on the admin panel to see recent comments, reports, etc.
Potentially alongside a banning feature, an ability to setup custom moderation filters for comments could also be useful, such as banning hateful or obscene language.