How about let's make it more simpler. I suggest using these "stars" as rate of how good a reporter is.
Here's an example :

Activity:
Merit:
Post:
            = Good Reporter (300 Good Reports)
       = Excellent Reporter (1000 Good Reports)
  = Legendary Reporter (5000 Good Reports)

This is what it looks like.




Optional
And for those who have lot of Bad reports.
           = Not Good Reporter (100 Bad Reports)
      = Bad Reporter (200 Bad Reports)
 = Worst Reporter (300 Bad Reports)

Edit.
if GoodReports >= BadReports then Good Report Stars will be shown.
else
Bad Report Stars will be shown.