OK, but what does this do that you can't do say in Lightroom by adjusting the various exposure controls and the tone curve and then tweaking the vibrance, or the saturation and luminance of particular colour groups in the HSL tab?
Quite a few things, actually. If you adjust Vibrance on the main tab, or adjust saturation and luminance on the HSL tab, you are adjusting the entire image (in the case of the HSL tab of course the adjustments apply to particular color ranges). The chrominance and luminance opacity sliders in NX2 will only affect those pixels that are the subject of the particular adjustment at issue. So, for example, an adjustment to the tone curve might apply to a limited portion of the tone curve such as highlights, but the vibrance adjustment to correct for any unwanted color effects would affect all pixels throughout the tone curve. Likewise, if an adjustment is applied locally through the use of a mask (adjustment brush in Lightroom) the chrominance and luminance effects in NX2 can be adjusted for only that local area, whereas in Lightroom, the HSL adjustments for example can't be applied locally.
More broadly, the benefit I see in the NX2 approach is that one applies only the desired amount of chrominance or luminence effect to any adjustment as it is made, without worrying about how to undo the effect in a separate step. Of course, many are comfortable with using LR and I'm not arguing against it, just trying to respond to the OP, but I'm still not sure if the NX2 feature is the sort of thing the OP is talking about.
