Some sort of "entry level" FX body makes a lot more sense than having a higher end prosumer DX body. I don't think we are going to see the end of DX, but that the DX bodies going forward are clearly going to be aimed more towards the 1st time DSLR buyer.
I do think that Nikon is going to finally start making FX more affordable for the "masses". If this erodes the higher end DX market, I am all for it.
Yes, it is a bigger sensor (by a 3rd), but the price jump into FX has been astronomical.