That said -- I've sort of thought for a while that the display should actually be decoupled from the device. I have a phone, a kindle, a smartwatch and a laptop -- all of which have separate user accounts, need cloud syncing (blech) and in general are a PITA to manage. I'd much prefer it if I had a computer on my wrist, which could wirelessly connect to external displays (Miracast?), and make use of them. So, my phone, kindle, laptop -- even a new tablet! -- are all just differing views of the same actual computer.
I'm imagining a world where monitors, keyboards, touchscreens, etc. are all just dumb devices with a network connection, interfacing with a nearby server, which acts as a hypervisor platform for nearby peoples' operating systems (which might 'follow' a person from home, to work, to the grocery store). Brushing aside privacy issues, it almost seems feasible - and infinitely preferable to the fragmented mess we have now.
And assuming power/computing requirements are able to satisfy the technical demands in 5-10 years, I can imagine small breakouts in eye-wear, wristwatches, and if I look a bit farther (10-20 years), I can imagine it breaking out to the clothing market.
But I'd have to say I'm more intrigued into how traditionally ephemeral everyday situations will be cataloged and increasingly available for everyone else to see, where the battles will arise, where the new opportunities will lie, and what social systems will be shaken up.
Smartphone builders had similarly vague ideas about which problem they were solving: they knew they needed to give access to some dumbed-down subset of the web and of our computer data. They knew that mails were part of that subset. Mail is easy, it's SMS with a different transport protocol, right? So they were looking for a dumbed-down keyboard, dumbed-down mouse, dumbed-down windows, scrollbars, etc.
The iPhone took a mile-high view of the problem. "Dumbed-down mice (stylus) and keyboards suck. How do we make them superfluous? And how do we get adequate access to non-dumbed-down Internet, too?"
Now with the watch. We have some vague fragments too. We know when we don't want to take our phone out, so in each of those cases we plan to use the watch as a dumbed-down phone screen. It's probably touch-sensitive, too (in a dumbed-down way no doubt), and it lets you awkwardly have a subset of the interactions you'd have had with your phone. So, I bet that watch is nothing but a dumbed-down proxy of our phone.
I'm still waiting for someone, not unlikely Apple, to show me what I really wanted from a smart watch, without realizing it. And if apple figured this out as well as they figured out the smartphone, the Google-wearable guys will kick themselves during the demo, the way the Android guys decomposed themselves while Jobs was showing them what they should have done.