When setting up margins and layout it would be great if the user could customize the width of individual columns. For instance I start a new document that's 8.5 x 11 with 2 columns and a gutter that's .25. At some point, either the initial document creation or after, it would be amazing to change the width of one of the columns and in so doing it adjust the width of the other column while keeping the gutter the same. This would help for much more dynamic, asymmetrical and feel visually more organized than simply bringing in rulers. Horizontal rows would be rad too.