Interesting video:

Maybe for Cortana to take the next leap it needs some sort of dedicated sensing hardware - our phones are a great starting point but Cortana doesn't know when we are hot / cold, hungry, tired, having fun, sad, sleeping, what we are eating etc etc.  If Cortana knew more about us and what we are doing right now then for sure it would be Big Brother scary but potentially incredibly useful.

OK, Shoot me down ....