That problem was short-lived, you've been able to rate songs from within iOS Music for some time now. Maybe you didn't enable it? (Settings > Music > Show Star Ratings) Doing that allows you to view and change the rating, but honestly I prefer the Cesium widget for making rating changes, fewer steps involved.For instance, the iOS Music app jettisoned star ratings a while back in favor of "Loves" which is just beyond useless.