Comment Smart alarm, navigation, payments, standalone (Score 1) 427
A few things come to mind.
1. A sleep tracker and a smart vibrating alarm, so I could get the most from my sleep hours and not wake up my wife and baby. Something similar exists and does not require an OS like Android, but would be a nice feature for a device like this.
2. Solve the city navigation. To the level of "now which exit should I take from this subway station?" and "now where is this bus stop I'm supposed to take next?"
3. Electronic wallet, if they can make it universally acceptable.
4. It would be nice if it could replace the phone for calls and maybe music, even if phone calls are not as convenient and are only meant to be a backup option. It has to work as a standalone device without also carrying a phone in your pocket, anyway. Optional software integration is welcome.
5. It must work at least a week without recharging, and maybe have an optional wireless charger you could use at your work desk without taking it off. Battery life is more important here than the display colors or the ability to play video.
6. There can be different screen sizes (jewelry to PipBoy 2000) and different price points. It's going to be hard to balance the screen, batteries, looks and price. If you want it to be popular, there has to be a $100 version with limited functionality, a $300 version that replaces all the main smartphone functions (maybe use a flexible/curved 4" screen), and multiple $1000+ fashion makes.
All these features don't have to be present in every device. For example, I would not use a 4" device for a wearable smart alarm.