Having the reputation of the user whose post is being flagged is a useful piece of information - especially for "not an answer" flags. If the user has less than 50 rep - i.e. a new user - then they are less likely to know the rules that govern when you can post a comment.
For an established user simple deletion would suffice, but for a new user you might want to leave a follow up comment explaining why the non-answer was deleted and encouraging them to participate enough to be able to comment.
Please can you add the user's reputation to the information on the dashboard.