Part of the problem is that everyone has a different definition of 'waxy skin.'. For one thing this term seems to be used exclusively in reference to Fuji. When people talk about excessive noise reduction on other brands of camera they tend to use terms like 'smearing of details'.
Personally, I think that what makes the effect different on Fuji is just X-Trans (any generation). X-Trans requires a fairly heavy amount of chroma denoising/color smoothing (usually built into the demosaicking processing step) to remove false colors. Without this step, which Bayer demosaickers have historically skiped entirely (most Bayer sensors having AA filters), X-Trans images of skin would contain lots of green and magenta artifacts at texture edges. With it, skin tone is smoothed out. You'll notice that in comparisons between X-Trans and Bayer images, the veins in peoples eyes are always gray/flesh-tone in X-Trans and (correctly) red in the Bayer images. This is the kind of detail one loses with X-Trans. NR -4 brings back the luminance noise, but it doesn't really bring back the chroma detail.
All of this being said, it's still a somewhat subjective matter where personal preference plays a large role. And if you're not the type of person who zooms in to 100%, you may never even notice the lack of chroma detail.
Life is full of compromises, and if you want Fuji's sharpness (in lenses and sensor output), you may just have to decide to life with their sub-optimal CFA and camera ergonomics. (or wait for the Bayer medium format camera!)
