Please explain your first statement. I have trouble understanding how simply electing Obama made things easier for us in regards to world politics - that is a very vague and subjective statement, and I haven't seen anything happen in the last four years that only happened because of improved world perception, other than maybe that laughable Nobel Peace Prize. Perhaps we experienced far less fallout over intervening in Libya than we would have under a Republican president.
In regards to your second statement, you are likely correct. In comparison to McCain/Palin, Obama definitely improved the perception, if not the reality. And I am cynical, because that is the only reasonable response to American politics at this point.
And in regards to the third, so be it. They shouldn't have to worry about how we perceive their leaders. If they do, it's only because we have the world's most powerful military and both Democrat and Republican alike have shown willingness to use it.