I totally get the waxy issue. I dealt with that in the past with skin tones.
But lets put this in perspective. You are whining about the effects at 6400 ISO! We have all gotten so spoiled with the technology that is available to us anymore. Maybe I'm showing my age (44) but people seem to forget what it was like to shoot with film. These images would have been a dream compared to some film stocks pushed to 6400. Not to mention that you probably shot these photos, downloaded processed them, compared them, wrote a blog post, uploaded the images in the same time that it would have taken you to go drop off you film at the lab.
Yes, Fuji can definitely improve...just like Canon, Nikon, Leica, and RED. The joy is that we are in a world of constant improvement and a solution to this issue is probably 12-24 months away. Relax, its not the end of the world.
Reminds me of saying I heard the other day,"Girlfriend...you got white girl problems!"