For me

400/D710024MP DX sensor, would love some extra stops of noise performance, but seems unlikely.D4/D800 metering system, AF system (D7100 could have a lousier one) and processor (D7100 could have a lousier one).Pop up flash.100% viewfinder and preferably larger.But then, it doesn't seem likely that Nikon will produce a D700 replacement, seeing that D800 is so successful. Even if they produced a D700 replacement, I don't expect the sales to be as strong as you said. The noise performance isn't much better than D700, though the AF, metering and processor system is enough of an improvement.To me, D400 seems likely, but not a D710 or whatever it is. D4 is to compete with 1DX, D800 is to compete with 5D3, D400 is to compete with 7D(2), then what would D710 compete with?EDIT: IMO, it's either D400 with the 24MP sensor or D710 with the 16MP sensor that will be announced.