Great great question.
My gut is certification programs make solid B to B+ program managers. It makes sure you have the basic skills and knowledge to manage projects and a PMP, DAWIA certified is kind of a rubber stamp that you'll do a solid job.
However, the question is how do you develop A to A+ program managers? To me those are another level of skill. They definitely can do all the PMBOK, MS Project, etc...but honestly at the high level that's a given. The best ones I've seen at that level are great leaders and managers - know how to recruit and manage talent - both govt and vendors. They also understand and can play organization politics from dealing with internal politics to Congressional issues.
So how do we build those level of PMs? My gut - it's a mix of making them Deputy PMs of huge projects, sending them to higher level leadership/management training.