A mind map is essentially hierarchical data.  It would be really time saving to be able to not only view, but also edit mind map data as an outline.  It would save me so much time fussing around with a lot of point and clicks if I could just quickly brain dump all of my ideas.  It would also be really neat to be able to change their relationships within that outline view too, increase or decrease indents, move an item from one parent node to another, etc.  Think of all of the edits you could make quickly with out fussing around with creating boxes, double clicking to edit the name, dragging and dropping lines.