I don't have the training, I suppose, to rate an image on it's technical merit and don't rate images very often. But I think I'm probably in the majority. Probably many of the ratings are based on the emotions or such that a person "feels" when they view the image. IMHO that's where comments will tell you much about the ratings you recieve. I also don't think the ratings hold much merrit as to technical quality but may tell you more about the type of photo (or artwork) that people enjoy looking at. Generally I rate and image a 5 if I REALLY like the image for any number of reasons. If a photo (that IMO) would rate a 1 then I probably wouldn't rate it at all for a number af reasons... either they already know it's bad or I can't explain why I would rate it so low or I just didn't look at it.
Just some thoughts from a total amature.

Manning