Never max out your sharpness on DSLRs. It only creates more moiré and artifacting. I shoot with the sharpness turned all the way down to compensate.
I never was very fond of Neutral mode either; to me it makes unnatural skin tones. I used to shoot everything in Landscape mode, but now Cinestyle works wonders for flat light.
The following was shot in Landscape mode:
sharpness: 0
contrast: -3
Saturation: 0
hue: 0
I normally use curves in Color but I figure this will do...
First I exposed so that the whites weren't clipping (losing detail due to overexposure)
I started by raising the blacks because I found them too dark in the original file. Unlike normal footage, getting contrast in snow is the product of balancing mids/highs rather than mids/lows. So I dropped the mids to get more snow shadow, then raised the highs to compensate. I also gave the blacks a little more blue because in my mind's eye, I perceive flat light to be colder than sunlight.
Here's how it looked after: