So, someone leaked windows 8 discussion documents and uploaded them, and you can take a look at some of them over at Microsoft Kitchen
I just found it amusing that in this slide:
They are clearly considering their target audience as ‘everyone’ and have a slightly humorous (I think) section
“Why humans matter”
-Substantial in size
Other than that the idea of logging in by face recognition sounds abysmal. But the increased speed and ubiquitous settings through a cloud is more interesting.