You want a smaller watch but more features like LTE though. The current size can't handle using GPS, Spotify or slacker for a day. Your watch would be dead in a matter of hours. I run every day. I know what it's like to lug a stupid phone on my arm. I'd love a smaller device that could track my runs with runkeeper. The MAXX is great but not runner friendly. While biking it's easy, I just attach it to the handlebars.
Now only if they could figure out a way to charge the battery off our body(heat, sweat, etc). Then a smaller battery would be fine.
Actually charging off body heat and/or motion is the way that lots of high-end watches work now. For the body heat they use Thermoelectric generators based on the Peltier effect. When you heat one side and the heat dissipation cools from the other, you get an electric difference across the two sides. This is the technology used to power those portable refrigerators that can plug into your cigarette lighter in the car, and also those car mugs that can either heat or cool your drink, except that instead of applying heat or cold and generating electricity, they apply electricity and one side heats, while the other cools. Since reversing the voltage across the two sides reverses the heating/cooling sides you can make it both a heater and a cooler.
So they place one of these on the arm side of the watch and the rest of the case acts as a heat sink. This gives a very low voltage, a constant one, but still enough to provide supplemental power. The big issues have been the size of the Thermoelectric generator, that they are usually rather large, thick, bulky and do not bend, as well as the amount of voltage they generate for very small differences in temperature across the two sides. They're working hard to beat that problem back.
There is even a newer version of this technology that could easily be incorporated into watches.
This is one among many that promise to change battery power for wearable items.
Flexible Glass Fabric Arm Band Converts Body Heat Into Electricity Ecouterre is very thin and flexible, so those are two of the biggest issues that have stood in the way of this technology. The third is also addressed her since as you can see, it's generating nearly 3 volts with just the wrist.
The ones that use motion take advantage of a tiny electric coil and magnet generator and a concentric weighted wheel that spins as you move your arm. Depending on the angle your arm is, will determine where in the middle of a revolution the wheel sits and as it turns it moves the magnet past the coils creating an electric charge.
Both of these systems have been in use for many years, but they have only had to provide miniscule amounts of power to keep the mechanisms in watches moving. Today we are looking at OLED screens that draw hoardes more power, microprocessors, RAM and more, all consuming large amounts of power and making the task of providing that power so much more difficult.
However we are nearly there. This could be the future for us in as little as a few years.