Noise is noise, and no matter what the magnification it reduces dynamic range. The reason is that something that is correctly captured as pure black but is affected by noise has only one way to go: lighter.
Even for examining "fog", the only fair comparison between sensors of different pixel counts is viewing prints of the same size, or failing that, images at scales that correspond to the same total image size; not comparisons at equal pixel display size, which, I will repeat, is like viewing different negatives of different sizes at different magnifications.
Also, most photos contain little pure black, and most of the discussions of noise level are based on less completely dark parts of images, so while the fog level is one issue, there are other aspects to noise level comparison.
At anything significantly above fog level, where most shadows lie in a properly exposed image, the RANDOMNESS of noise means that it is somewhat averaged out and hence reduced when one used more pixels to produce a given part of the print; roughly, with four times as many pixels (D30-14n), the visible noise level in the print should be reduced by about a half.
With criticism of the 14n, we seem to be into the stage of "taking sides and piling on": once significant, legitimate criticisms exist, and so an overall adverse mood has developed, some people become more credulous of other exagerated, sloppy, cynical and speculative critical arguments, while being more vigorously skeptical of any arguments in the contrary direction. I would like to hear a bit more objective assessment of "what things can it do well, and for how many people do these strengths make it worth the price?", which is how I would assess the significance of almost any product. If it can do a few useful things better than any other digital camera at anything close to its price, it probably has a niche.
