Selective permissions sounds like a bad idea to me. I can just see users thinking, "Why does my music player need access to my call state?" Disallow. Waaaah, why does my music not stop when a call comes in? 1 star. For the most part, developers know what permissions their app needs, and they're not adding permissions without good reason. Maybe there should be a place to explain what they need them for to the users, but allowing users to turn them off will just lead to headaches.