Let's not forget what people thought digital music players should look like before the iPod, or what they thought that Apple's phone would look like before the iPhone came out. Everyone was wrong. My gut feeling is, the iWatch will be surprising. It will not look like a watch as we think of watches today. I could be wrong, but this is Apple we're talking about. The things we can easily imagine have already been done before. Apple's expertise is in imagining things other people haven't imagined, and it's somehow better.
When I think about smart shoes, the first thing that comes to my mind is kinetic energy. You can actually get electricity from the impacts of your feet on the ground. There's been talk of utilizing that sort of kinetic energy from floor panels in buildings to make buildings greener. But what if you could harness that energy from people's shoes, and have that energy charge other wearable technology? I think such a "shoe charger" is not going to come along for a number of years, but it's interesting that Apple is hiring more and more wearable tech designers. Kinetic energy, though, can definitely be used for watches, and already is. I wouldn't be terribly surprised if an iWatch used either solar charging, kinetic charging, or both, rather than a battery you need to plug in. If the iWatch is being marketed especially towards active individuals (and it seems Apple has a big focus on that lately with Nike partnerships and the M7 chip), kinetic charging would make a lot of sense.