1) Monitor and keep and continuous chart of blood glucose, sleep cycles, blood pressure and pulse rate, blood oxygenation. Don't even know if the tech is viable for these, but they'd interest me.
2) Be part of a payments system that actually gets traction out there. Let me import all of my cards of various kinds and then provide them wirelessly to others without having to pull out a card (and/or a phone with a specialized app).
3) Same thing, but hold all of my tickets for entry into events.
4) Connect to a voice-to-text service to enable personal logging/journal-keeping just by talking at it.
5) Find a way to operate clearly and reliably using gestures and voice recognition rather than touch input when desired.
6) Have built-in GPS and voice navigation.
7) Have a built-in high-resolution camera to enable convenient visual capture of information.
8) Do all of this in a cloud-based manner so that everything that the watch did/tracked was available from all of my other tech devices.
9) Have a between-recharges time measured in weeks.
I don't know, it would have to be pretty freaking fabulous. But there are some basic things that I *don't* care if a smartwatch does, and those are probably more telling. I absolutely do not care about doing these things on a smartwatch:
6) Linking it to my phone via bluetooth
7) Telling time
Number 6 in particular is a non-starter for me. Battery life on phones is already too short. And phones are the devices that I use for web, email, and other informational tasks on the go because they (not a smartwatch) have the screens suitable for reading/editing. I need them to last as long as possible, and I have no interest in duplicating their functions on a smartwatch. So I refuse to enable bluetooth on my phone all the time just to get some additional "watch" features.
It needs to be a "standalone" device in the sense of no other devices needed for it to operate normally, but a completely cloud-integrated device in the sense of "but I can access everything it does and it can access everything I do on my other devices over the network."
Number 7 is also pointedly interesting. I don't care if something on my wrist can tell time. Social "time" as a concept is more ambient than ever. Everything has a clock on it. Your computer. Your phone. Your thermostat. Your radio. Your car dash. Every ticket machine of every kind, from movies to transit to events. Public spaces and the sides of buildings and billboards and retail shop signs. I don't look at my wrist or my phone to know what time it is. I do a quick visual 360 and in general, I find what I'm looking for, wherever I happen to be. A "time-telling device" is frankly a bit 19th/early-20th century a this point.