Obama's legacy will the 2 big things: The first Black Pres and the nomalization of health care as part of the social contract. Those are two pretty huge things and history should never underestimate them and how much those two things limited the rest of his scope of action.
But he did have plenty of faults as well - he was naive, or at least lacked sufficient depth of perspective on many foreign policy issues, ignored the health of his political party, was too conventional, even conservative in his economics - leading to the red party getting the best of him on too many economic issues. Still, he was one of few presidents to actually move the country on a major policy issue, and for that he can be forgiven a lot. And maybe, hopely, in the end the country ends up better for having to look in the mirror over the backlash his presidency unleashed.