Nice idea. A few things though:
first, there should be a way to go up in the hierarchy.
second, would be nice if you could make the menu rotate using the mouse wheel.
third, better graphics/icons will really help.
fourth, and the MOST IMPORTANT one:
i have a lot of options in the regular context menu (added by the 50 or so addons that I use) and I use all of them. So I've set the radial menu to appear only when dragging. (Great option, btw, thanks for it). But I'd really like to customize after dragging how far the radial menu appears. Currently it seems it appears even if I drag the mouse a single pixel.
It'll be a great addon for me if this fourth thing is fixed. :)