Hi Andrew,
-- regarding the image which "graded poorly":
I believe this happens not because it's flat but because the whole thing is dark. That sounds simplistic, but in my understanding the gamma encoding of digital images in relation to light means that the darker areas get fewer bits accorded to them than brighter areas. Dark areas of digitallly photographed images literally have less information. This is why digital imaging in general has such a problem with shadow noise and why a well exposed image looks great in the higher tones and still looks bad in the shadows, and why everyone "crushes the blacks" these days. It's why professional video is so obsessed with 10bit and 12bit images too, because it's the only measure you have against this problem. Chemical photography doesn't do this, since it "encodes" information linearly in relation to light level, so it all looks much more even.
Anyway what I'm saying is with a flat profile if you push your exposure "to the right", even though that looks wrong on your display (it will all seem too bright, but just watch your histogram), later you will have encoded more of the picture you actually want, since the flat profile allowed you to push it in to the higher levels of the image. In the grading you would bring things down (rather than up, as you had to do with the sky in that image), and you find that the tone and saturation will turn out much better. That's my theory.
I would like to see a comparison, to see how the NEX 7's flat image profile would hold up if treated that way, since I think the color looks much more neutral and balanced than what the GH2 or Canons produce...
Best,
L