i doubt there will be private replies any time soon. i remember reading in a thread that they would not want to moderate private messages. maybe if there would be an option to make reviews public, so people could at least read why a game was rated high or low. but if you scroll the public rating feed, most people do not write anything.
in the meantime, you could post a comment in your own game, asking for feedback and bug reports there, so that you can fix it, instead of negative ratings, just because a button did not work.