I suspect we actually have similar views on this - as you said: "...the magic ingredient is probably the dof, dynamic range, noise performance...".
It's quite true that the D700's high-ISO noise performance is clearly better than a D300, and its dynamic range is a little greater in many circumstances. Depth of Field differences are down to the format, not the specific camera design, and of course can help or hinder depending on what effect you want to achieve.
I've just been trying to counteract the view that the D700 has something "magical" that can't be quantified, over and above the technical differences
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