One has to guess what is in Nikon designers' minds, as the D700 + MB-D10 was 80-90% of D3 and sales were over the roof, and D3 sales were likely not resounding. Then came D3s and the decision to not update the D700, that probably pushed D3s sales much higher than D3, which to Nikon would have validated the theory that a "cheaper mouse trap that is as good as your most expensive one" will impact your bottom line. So we will, IMHO, never see another FX version of a DSLR that will do 80-90% of the top of the range DSLR.
Nikon's strategy is to segment up the market
- pro high frame rate, crazy ISO: D4s
- pro high frame rate, crazy ISO cheapskates: too bad, cough out for D4s
- pro high pixel resolution: D800E/D800
- pro, high frame rate DX: rumored D9300
- pro/serious amateurs/nostalgia, crazy ISO but can work slowly: Df
- serious amateurs: D610, D7100
- entry levels: D3300, D5300
With the rumored D9300, it seems Nikon is finally realizing that there is a DX group that demands pro features but do not wish to go D4s. The current strategy appears to be D300/D300s to either choose D800 (same pro feel but slower frame rate) or choose D7100 (seriously crippled buffer). Nikon may realize that a pro-spec DX body will not be directly competing with D4s, although in some instance it may, but mostly DX/FX divide is sufficient to keep some serious amateur or pro steer clear of using the rumored D9300 for certain type of work.
But I think the rumored D9300 will also attract pros who shoot birds, animals, etc as well and use it as a second body.
Will the rumored D9300 feature 16 Mp or 24 Mp? My guess is that it will be 24 Mp and Nikon will let DX/FX divide separate D4s and the rumored D9300.
I think, that the rumored D400, rumored D9300 all existed as prototypes. I think the success that was D300/D300s must have kept the prototype development alive, but the top brass over-ruled the decision as they want people to buy high in the series.
So if you see my listing on Nikon's strategy to segment the market up, my guess is that the rumored D9300 will be priced high, likely Df price. Definitely higher than D610 pricing.