It's placed higher in the model line than the D700 and the D600 is placed lower. It appears that the D700 has been orphaned. Perhaps there'll be more announcements in the coming days. But for now, that's what it appears.
The D800 was released at the same absolute price point as the D700 when it was released, so I am not sure why you consider it placed higher besides for the number, but that only indicates a change of generation?
Considering the inflation that happened in 5 years in most countries, the D800 is de facto cheaper than the d700 was. There are of course some exchange rate issues making this a bit more complex since the US$ lost 60% of its value relative to the Yen in the meantime.
As I said previously, the D700 was and is a very fine camera that met the needs of a wide variety of photographers. With these two new cameras, it seems as though Nikon may be moving away from offering such a wide ranging feature set in a single camera and being more, for lack of a better term, narrow in its approach. And that may come at a significant cost.
What exactly can the D700 do that the D800 cannot?
I have been using it for landscape, street shooting, action, architecture and some portrait recently and just cannot find anything it doesn't do much better than the D3/D3x and by extension the D700.
The only thing coming to mind is framerate, that's it.
Nikon set a precedent with the D700. In some ways a similar precedent as Canon set with the 5D. Canon has, seemingly, been willing to continue on in that vein where Nikon perhaps has not. At the rate that D800's appear to be flying off store shelves, maybe it was the right move. For Nikon, not necessarily for the end user.
Again, what is the actual downside of the D800 compared to the D700 for the end users?