Obama, Bush, Clinton, etc surrounded themselves with smart people, and consulted with them before talking. Bush was prone to bush-isms, but the thing is that they trusted their people and learned from them before speaking, nevermind making policy decisions.
I don't see this from what little I've seen of Cain. He seems to think he already has enough information, and makes decisions based on his limited perspective. I could be very wrong - in which case the problem is that he's surrounded himself with equally stupid people, but in general successful people surround themselves with smart people and hash things out continuously with them until they understand the situation well enough to make a decision.
Half of politics is networking, the other half is superior firepower.