I'd like to request a column in the Library pane that shows whether a resource had been downloaded to the device I'm using. One might call it "Local," "This Device," or "Downloaded," thereby differentiating it from "Devices," which provides information about mobile installations. A checkmark or "Yes"/"No" in the column would be sufficient.
No, the filter facet on the left side does not meet this need. The functionality is quite different from a user's perspective.