Everyone needs a file system. However files that need to be used frequently can live on your desk in something like this. I like that it's flat rather than graduated and has side enclosures. Keep those papers safely tucked in one spot!
Home office: Perhaps the full-wall shelving unit goes on the wall between the new office and current office? Then the window wall is left without built-ins around the window and the adjoining wall is open for artwork. It would look bigger.