warprints: I spoke of need; not want. Sure the fast f2.8 lens will always be in demand by someone but that someone may not be Major Floppis or me. I just finished a season of photographing high school basketball in dimly lit gyms. Using a D7000 because it has the cleanest high ISO image at ISO 3,000 to ISO 6,400 and using a shutter speed from one 320th to one 400th of a second to stop the basketball, I often needed a f2.8 lens. But if the D4 does give us a cleaner higher ISO up two f stops from the D3s then we can set the ISO to 12,800 or higher (whatever still yields a clean image) and drop our f stop from 2.8 to 4 or 5.6 and still do what we had done with the f 2.8 lens. This can allow us to use "normal" lenses and not have to pay huge amounts for special 2.8 lens. I think that would be a great benefit for sports photographers and drastically reduce the cost necessary to freeze sports figures.
The NEED for the 2.8 could disappear for sports photographers. Sure, they can still use it if they want and it may still be necessary to stop motion for certain high speed sports if you will be needing shutter speeds shorter than one 500th of a second.
My point is that the need (as opposed to desire) for the "big" lens may no longer exist. A D4 may be able to freeze action at f4 and one 400th of a second because it may be able to use a high grainless ISO which is two stops higher than the highest grainless ISO of the D3.
We will just have to wait to see how it actually performs when it is released and people get a chance to work with it.