I do know I can edit ratings in Now Playing screen and showing 5-star ratings in a playlist is possible. However, sometime I want to edit 5-star ratings directly while scrolling songs in a playlist, albums, and so on. Actually, “favourites” flag has a quite similar UI. In a playlist, click the “triple-dot” button of any songs, then there’s “Add to favourites” button to edit favourites directly. So, I think 5-star ratings UI made better like this. AFAIK Dsub has the feature that I just explained.