Ability to scale a window's resolution
I spoke with Ken about this in IRC a week ago.
Basically this allows individuals with lower Resolution screens to be able to scale windows down to elimimate extra padding/whitespace that may exist in an application. Ideally this would be able to be done on a per application basis.
An example of this is how this would look is how you can scale a webpage in Chrome/Firefox; however for this to apply to ALL UI elements within the selected window.