The African American vote is not very important for the Electoral College. In the states where the African American population is big, almost all the whites vote Republican, and then, the Republicans take all the delegates of these states.
New York and Maryland have also high African American population, but in these states, the Democrats win even without the African American vote.
The hispanic vote is much more important for the Electoral College, because there are many hispanics in swing states.
Umm what?
Obama relied on the black vote to win Virginia. Philadelphia delivers Pennsylvania to Democrats basically because of an overwhelming black vote. Even in states like Connecticut, if you factor out the black vote the state becomes much more competitive.