D800 AF now IMPROVED!

Good point.  I was thinking of my own D600, and the other thread that discussed it.  I don't find the D600 has enough dynamic range to ignore exposure...and Nikon's matrix metering isn't very reliable, in my experience.  Exposure control is pretty high on my list...somewhere right after focus and composition.  I can tweak composition easier in post than blown highlights.  The only advantage I see to AF-on, would be improving focus (if it did.)  I've used it before (on another brand) and found it mostly different...vs. better.  But, if it allowed the Nikon to continue to tweak and improve focus...vs. lock too soon and inaccurately, I would try to figure out a way to use it with the D600.  Perhaps someone who does use AF-L and exposure lock could suggest their button assignment.