Next gen of this watch would have no wifi, use a small micro controller like a ATtiny 85, possibly add a RTC and small coin battery. Only use LiPo to drive the neopixel display.

Should yield a "works all convention long" (3-4 days) run time as apposed to 1-2 hours continuous on run time now. or 1-2 days run time with power off when not using.

see http://www.instructables.com/id/ATtiny-Watch-Core/ for info & insparation (without RTC module)