I agree, I am currently sharing just over 2000 files but have the ability to still appear to be sharing them but restrict upload slots to 0.

The rating system would have to include a number of factors, some members share large numbers of files but due to either the file names giving no indication of what the contents are or just sharing stuff that no one else wants they would not be making a contribution. One of the stats recorded should be the MB that other users have actually downloaded from the client.