I think this gets way over thought. The MF look was there when we were only shooting film, so that tells me that it's not CCD vs CMOS, CFAs, MLs or any other acronym. It's driven by sensor size, and to a lesser amount, lens rendering style.
Sensor size defines secondary magnification (sensor size ––> viewing/print size). With a larger sensor, the final image is magnified less, resulting in smoother tonality. This was completely obvious when comparing 35mm to 6x7, more subtle now that we're talking about MFD which is < 645.