I haven’t read about this in most reviews of the Nikon D810. It’s a small, but very welcome addition to customize your camera settings. You can now limit the selection of AF area modes. I for example never use neither 3D-tracking nor Auto-area AF. Now I can disable them in the menu a11 Limit AF-area mode selection.
This is useful when you quickly have to change your AF-C modes. To bad you can’t also disable Single-Point AF since I only use that with AF-S.