Something to possibly consider because we have a new ability with the addition of Area Close.
Right now SCREEN_OT_area_dupli breaks out a new window, created as a duplication of an existing area. It works great (although I think the window might be incorrect size on Mac Retina). However, the operation is never enough on its own and always must be followed by further operation. This is because it makes the new area at the location of the old, and the old area remains. So you don't gain any utility instantly, you just have two identical things with one obscuring the other.
With this patch install the old area is closed when the new area is created (as long as the screen contains more than one area). This way you immediately have more space in the original window, which is very likely the primary reason you called this operator at all.
