I would love to get "Hey Siri" to work while my iphone6s is in my pocket. My Apple Watch could be the mechanism to do this if required. Why? it has to do with handsfree automotive use. I find it dangerous to fish around in my pocket to hit the home button so Siri comes through on my auto bluetooth handsfree system for calls, messages, ... Taking the phone out for long trips works OK but I find it frustrating on shorter trips.