The iPhone was built around a consumer, iTunes-centric model. Sure it can be made to do a lot more and eventually it likely WILL be possible to create (or exceed) BES-levels of corporate management solutions for the device.
But honestly, I expect this to come from a third party first. In fact, I wouldn't be at all surprised to find that either Microsoft or RIM themselves get into "policy mangement" for iPhones to support mixed-device environments. Long, long before Apple does it themselves. Its just not their priority.