I would rather see most apps just use intents:
Need an image because you are the QR-code app ? Ask the image 'app'. The user can pick to choose the camera app and make a picture if he/she wants or grab an image from the image gallery app.
Need a contact ? Ask the contact 'app'.
Now most apps don't need any permissions any more. And the user knows what data the app gets because the user chooses the data and the app the data came from.