Thinking a little more about interface innovation for touch

I was thinking today about yesterday's post re: Apple's seeming confusion about whether to truly be "touch first" or focus instead on keyboards or styluses for input purposes. Clearly the end goal is to make the iPad a more productive device for creating and editing content and in that vein a keyboard and stylus may be the way to go.

But an interesting question to consider would be: outside of these two tried-and-true methods of input and voice, what else could the company invent? Gesture recognition seems obvious and given that they own Primesense there is a good chance that will come (probably after getting into an Apple TV) but looking at my desk today with both an iPhone and an iPad on it, another idea hit me: why not use the small touch-sensitive screen of the phone as sort of trackpad device? And extending this more broadly, why not use all of the other Apple devices through Bluetooth Le connections as good for input— for instance a Watch as a gesture recognizer or an actual laptop for fully complementary keyboard and trackpad?

As we collect more screens and sensors in our lives, connecting them in this way may actually give way to much more interesting interfaces for input than we can think of by just bolting on the traditional stuff. And given Apple's unique advantage in getting all of these things to talk to each other, this might be a unique playground for them to try.