Its awesome they're adding it but still needs improvement. I noticed this about a week ago.
As many have said, if you use the spotify app, it locks the phone. This is the same as the pandora app. However if you want to use spotify over the bluetooth, or even the usb cable and use your phone, dont select the app in the iDrive. Select USB or Bluetooth and it will still play the audio with limited controls
Then again why are you guys needing to use your phone while driving
???