I finally sat down and whipped up an image of a thought that I've been meaning to post for, oh, a few years now. I just happened to see another post today about the various watch phones that are starting to appear in the marketplace, and figured I should write about it before it was too late.
Rather than expecting a user to have to lug around a Bluetooth headset in order to use a small mobile phone on their wrist, it should work like a normal phone does. Here's how: I bet that by adding a tiny speaker/microphone into the bottom of a watch's strap pointing towards the hand the user could cup their fingers next to their head to bounce the sound into their ear and be able to talk directly into their wrist. Remember those insanely tiny candybar phones circa 2002 that you had to do this for anyways to hear? Same thing, except it'd be on your wrist all the time.
They should get rid of all the extra nonsense like full color screen and just make the whole thing as tiny as humanly possible - with a scrollable LED addressbook synced to your computer and the ability to dial numbers in the same manner you usually set the time on digital watches. The massive mobile phone watches I've seen so far are just ridiculous. I - and everyone else - would rather just carry a phone with us.
Just a thought.