Nice looking camera. I prefer the look of the Coolpix. Also, having gone through the Coolpix manual, I feel that the Nikon has some nice UI features that the GR can't match.
Having looked at the DPreview samples (the "test chart" one) I can only conclude that there's something off. Either with the cameras themselves, or in the taking of the images.
The upper left crop they sampled is by far the worst corner for the Nikon. I would actually say the the far left side favours the Ricoh. The right side is a different story. In some areas the Nikon is clearly better and that includes an area in the upper right just before the corner. The Ricoh only tops the Nikon in the extreme right corners and that, I think, is down to better handling of CA.
I don't think you can draw any absolute conclusions from these samples.