As duplicate allows you to place multiple copies of the object when you first place it, I'd like to request shift gets reused as a modifier key for copying. Currently when you copy/paste, it moves the object according to where the mouse is, which can make it painful to line up exactly with an existing object. I'd like to request therefore that if you select an existing object, hold shift down, and use the arrow gizmo like you were moving the object around, that you instead move a copy around.