(iOS 10, Android Oreo, Windows 10,etc.)
Right now the only way to remove the current song from the playlist is to navigate to the song in the playlist view, which is really annoying for every song.
You should add the option in the menu of the player itself (album art) of the current song. It would be way faster to remove it directly from there instead of going to the playlist view every time. Unfortunately now there is only the option to remove it entirely from the library, which is confusing and can be mistaken for removing it from the playlist.