I'm hoping/thinking this is where Microsoft is going with the streaming OS stuff. My understanding of the patent is that it allows them to load portions of an OS from diverse sources.
The way I see it, they could load the portions you need, not only of your documents, but also based on the class of device you are using. It doesn't have to be streamed from the cloud, theoretically it could be streamed from any device, though cloud syncing is an obvious one as well.
I'm with you on most of the things you say, but I add the further caveat that I don't want multiple 'devices'. If Microsoft can stream OS to specific hardware, we may break out of the 'device' mentality. I have an external monitor on my laptop. I don't consider that a 'device', or my mouse, my keyboard,etc.etc. Can we get to a world where we think of all the objects we interact with as nothing more than I/O. Like a pencil and paper?