Just sent this feedback to Apple, if you agree with it I suggest you do the same as the more people submitting it the more likely it will be added:
It would be good to add a song to the on-the-go playlist as you're listening to it.
Suggestion- when you tap the screen while listening to a song and the scrubber controls appear, there could be a plus (+) button on the bottom right corner. When tapped, it adds the song to the current on-the-go playlist.
If you agree, copy/paste this into Apple's iPhone feedback page- http://www.apple.com/feedback/iphone.html
It would be good to add a song to the on-the-go playlist as you're listening to it.
Suggestion- when you tap the screen while listening to a song and the scrubber controls appear, there could be a plus (+) button on the bottom right corner. When tapped, it adds the song to the current on-the-go playlist.
If you agree, copy/paste this into Apple's iPhone feedback page- http://www.apple.com/feedback/iphone.html