That's the trend I noticed too. "I use the rating system to flag songs that are my wife's so I don't delete them from the PC" "I flag songs that are x genre" and so on.
Just use the built in playlists and song flagging (is song flagging still in Zune 2G?) for that. I personally look forward to having a simple rating system. For all the people who claim 5 stars is the de facto standard for everything I'd say the most famous rating system is Siskel & Ebert's "Two Thumbs Up".