I think that it could be a good idea to have an option that shows the lyrics of the song playing or a selected song. This could be toggled on and off at the bar on the bottom that shows what song is playing. Or it could display lyrics of a song when you select it by clicking the ... icon to the right of a song then click display lyrics.
Updated on 2019-08-17
That's a great idea, but something similar has already been suggested.
You can check it out here.
Have a nice day!