I agree that Obama's popularity is high among most in the world.However, from a legal standpoint, that position doesn't currently exist. But, in some sense, followers of religions believe that their God rules over all. If one believes in God, their spirituality can be viewed as a relationship with the Divine. Religion is simply crowd control, in every sense of the word. That said, no God has yet managed to completely unite the world. If the position of world president existed, could Obama do a better job than anyone's God? I'll leave that up to each to decide for themselves.
Obama has been an amazing President which I'm sure will end as one of the greatest in history. I am still constantly in awe of the breadth of his intellect. If the world could have an election and each country was a state represented in an Electoral College of sorts, I agree he would sweep with the exception of those countries that are not allowed to have all the facts. Those countries that censor free speech and are grossly misinformed. Democracy still depends on an educated electorate. So yes he would win a general global election but there would still be some "red states" out there that he'd lose.