A simple idea, though it may not be coding wise, I don't know, I haven't coded a website before.
There have been many occurrences, one very recently, where I have found an error in one of my RMB posts, such as a typo or leaving something out, and am faced with two options; Delete the post and edit what it said, thus making another post, or quote the post and put the correction there, again making another post. This produce's spam on the RMB, as it could be easily avoided if we were able to edit RMB posts. We can edit messages on the forum, and I understand that that is likely because this is in fact a forum, so why not allow RMB post editing?