Hi there.

Although I have not watched the video yet, I'm going to make a suggestion for a future version of Hyper-V/Windows.

In one of the videos I watched, someone was explaining the advantages of creating VM's to test various usage scenarios for testing code.
My suggestion is to add a feature that enables you to create cheap VM's using the OS's files and only storing the deltas (similar to linked VM's). Maybe even integrate windows updates into those VM's or share the same memory for system files.
Basically, something in-between a VM and sandboxie.

I'm sure you probably already thought of something like that.

Thanks.