This is great news. I has shoulder surgery a few months ago and ended up buying Dragon NS to be able to work. It's very good software for dictation, but for controls and such, it's pretty lousy.
What I would like to see Windows do here is launch it with a regularly growing set of commands and voices to choose from. The consistency alone compared to Android should be excellent but if there's a good feedback forum where they can simply take user requests for commands and build them in and let users choose from a list to disable ones they don't want, that would just be awesome.
Something else they need to do. They need to make it simple to differentiate between multiple machines. I don't want to be sitting at my desktop with my laptop, phone and tablet and say "Hey, Cortana" and have 4 devices suddenly sprout for attention. Right now it gets bad in my kitchen with Google Now as I have a Nexus on my refrigerator, my girlfriend has a galaxy 10.1 inch. I have my laptop, we all have android phones, and when someone says "OK Google" they all want to go off nearly at once. They are just off enough that they hear each other and it becomes a comedy of errors. lol