Yes there is no getting around it, never close enough to wildlife it seems without cropping a little to a lot. I have found that the high iso shooting without a lot of post processing, fast frame rate plus the tank built like body and exterior buttons for quick setting changes is why the d4 is so good at quick action shots.
If a person requires a lot of extensive cropping then the d800 is better because it gets more pixels on the subject. I shoot with a Nikon 500mm f4.0 vr lens with converters at times when I need them to get more pixels on an animal. I try not to crop extensively and have learnt to approach animals better to get closer.
I rented a d800, tried it, then bought the d4 and have been happy every sense. The d4 is made to be roughed up in the field and comes out swinging.