An empty room in a dream often reflects potential more than lack -- space that hasn't been filled yet, waiting for a decision about what belongs there. It can also point to loneliness, depending on how the room feels: still and hopeful, or hollow and unsettling. The emotional tone usually matters more than the emptiness itself.
Oriental planets signifying either good or evil, perform their work speedily; occidental, more slowly. - William Lilly (1602.-1681.)