Robert Keahey makes a nice comparison of Software Defined Networking and Network Functions Virtualization.
Regardless if SDN and NFV, a robust information model and development environment is going to be required to make the transition from vendor-controlled, proprietary hardware and software to a truly abstracted, virtualized software-defined networking service delivery model. Obviously it will make it easier if SDN and NFV align and combine their energies to simplify the model.
The one requirement he has is still a big question for me. Will we ever get rid of vendor-controlled networks? I really hope so, but the past is not giving me any more hope. However, this is the time to change things, now we must build and keep the momentum to change the network industree, forever.