How to solve the 'phone' part of the wearable device?

That image above pretty much explains what I have in mind. Most of the wearable we have seen so far are mostly glorified notification system. While I don't really think this is the right way, see my earlier post on smartwatches here: http://tovganesh.blogspot.in/2013/09/it-is-not-calls-text-and-tweet-that.html

The problem with all the existing wearable tech is that you still need to carry around your phone. That essentially means you have to carry more devices when you are taking a wearable with you. What if the wearable device replaces your smartphone as well? With the phones getting bigger and bigger, I would like that to happen. The most difficult part, I think is to get the 'phone' part done correct (there is of-course the batter issue, but that is a different aspect altogether). And I think the perfect way to do this is to build a ring that can act as an earpiece. In fact, for most part the wrist and fingers for most of us perfectly fit in place to be near the mouth and the ears when you place your hand as shown above. I know this looks a little bit crazy. But if this done right, there is actually a revolution waiting to happen. I am particularly interested in the application and UI side of the smartwatch, it is probably the next wave of apps - should we call them wapps?

What do you thing?