Nikon USA consider the new announced Nikon D7100 as “The new flagship of Nikon’s DX-format HD-SLR lineup”, see the screenshot from Nikon USA website:
But from Nikon Europe website, Nikon D7100 is “the new enthusiast-level DX format camera”, see the screenshot from Nikon Europe website:
A dpreview forum member contacted Nikon Europe and asked them about the new D7100 being described as the “new flagship of Nikon’s DX-format HD-SLR lineup” on Nikon USA website, but described as “enthusiast-level DX format camera” in Nikon Europe. Nikon answer this question:
I can assure you that the D7100 is not positioned to replace the D300s as Nikon’s flagship DX-format camera – such is the information received from Nikon Japan on the matter.
So the successor of Nikon D300S maybe the Nikon D400.