There's been a lot of great discussion on what types of activities the new CTO should engage in. Let me offer this: The big-picture need is to tie open government efforts to this new push for competitiveness and government efficiency/effectiveness.
Attention and focus on open government have been waning, and I believe that the only way opengov will sustain into the future and be built into how gov operates will be for it to be folded into another big initiative. Obama's call for reorganization, in addition to the GPRA 2.0 bill that recently passed, offer the opportunity for opengov to "hitch its wagon" to something that has energy behind it.
I believe the focus should be how opengov can be built into the processes and culture of government. The early adopters have all bought in, but this movement has had trouble breaking into the rest of the bell curve. Steve's suggestion is right -- this is the position that should be building the infrastructure and resources for opengov to be *sustained*.