Take away the current ability to delete a review you have made once it has been posted for up to 1 month.
Right now, the way this current review system is working is, if you make a review of a server, it will save the review to your profile and you can delete it from there.
If you write a bad review and the server administrator comments on it, the person writing the bad review can delete it and then re-write it right away, remaking their bad review and deleting the comment that the admin made right along with it.
With the current way RMS works, it's left far too open to abuse of reviews and can easily bring a servers score down through tactics like this. I see this as one of the biggest faults of the RMS reviewing system right now.
At least with this rule, then you would be able to make sure that the comments made in the review are seen to all who look for an appreciable amount of time.