I use the music app to control the music in my car, and I find that I need volume control much more often than track forward/back. It would be great if we could choose which set of controls are the primary controls, or perhaps the controls just toggle with center button press and stay that way (at least during active playback).
I forgot to add that with the current system, if I wait too long between button presses while adjusting volume, I track skip which is very infuriating.