As I sit on a mint 200-400 Vr,2, the thought of the new one has not interested me. I find it very hard to beat the 200-500 F5.6. It's the lens I reach for now, over the 200-400, although wide open the 200-400 IMO has a bit better bokeh, it's just not a hand holding lens, at least for me. The 200-500 can be hand held and for wild life work I love it, especially birds, where I still prefer the optical viewfinder of the D810 (really only time I prefer it). For the best work @ 400 500mm, I still prefer a tripod on the 200-500, but it can at least be done. The 200-400 with the hood is massive and sure you can hand hold it briefly, but not for periods of time like I do with the 200-500. The ONLY fault I find on the 200-500 is the cheap flimsy hood.
Glad to see Nikon continues to improve a great lens, but as previous posted the cost and weight are out of sight and I just don't think it will that much sharper than a great copy of the 200-500, in the same focal ranges.
Paul Caldwell