I'm not following you on the focus point spread. My F100 had fewer focus points than the D2X or D3S. The F100 still worked. The D2X focus points were much closer to the edges of the frame. Focus still worked.
You could argue that the DX sensors limited the width on the FX cameras because Nikon didn't want to create two different focus systems. The D600 and up are all full frame now.
I see no restriction to getting more focus points to cover more area with the same density -or- spreading the existing points a bit for more coverage. My preference is to add points to the edges of the existing pattern.