Zoom! is a good word. I imagine something visual with sliders that allow you to magnify and minimize, expand and collapse, move in all directions. A dashboard kind of navigation thing.
It is hard to do something simple, pure and elegant. I think it gets to be much harder, or even altogether impossible, the more there are a lot of complicated requirements and legacy baggage and special interests bolted on to it.
I suggest starting with the simple, pure and elegant tool.