It seems to me that Ricoh is an oddity in the digital camera market. They are not mainstream, and they do not sell a great deal of digital cameras in North America. Yet, they makes some very nice and unique point & shoots when everybody else is make "me too" models. So when they introduced the GXR system, it was no great surprise.
Many people do not understand why the lens is welded to the imaging chip as a bundle. For one thing, the lens and the imaging sensor are the two most exensive components of a camera. By bundling them together, it is difficult to produce cheaply. It would make much more sense if the sensor and the lens are separate units.
I have a different take on this. The two lens/sensor at introduction is just the tip of an iceburg. The possibilities of this modular design is endless. You can have a different kind of sensor, such as black and white, IR, UV, whatever. There is no reason they could not make a sensor module without a lens, but a mount on it, just like a normal interchangeable lens camera. You can buy a M-Mount module, EOS-Mount module, Pentax K-Mount module, etc. Or, they could make a sensor module with a generic mount and produce an adapter mounts for it. Perhaps, Ricoh is a big fan of RED, whose digital video cameras are very modular, and they are trying to do the same thing as RED but with a digital modular camera!
Personally, I think this system has potential, if they survive people's initial resistence of this radical design. They do need to produce something that nobody else has to offer, such as a sensor module that only does black & white. Kodak made one, but did not sell in great numbers. I am sure the market is large enough for a B&W sensor camera.
We will wait and see.