There really is no entity called "history" that forms a stable judgment on the past. Instead, each generation forms a new judgment based on their own values and concerns, and of course based also on a longer view of how actions in the distant past have had consequences for future events.
Nevertheless, a good rule of thumb is that, from a more distant perspective, the human flaw of a hero makes him seem less remarkably good, and the story of the childhood of even a monster makes him.
My guess is that in a century or so, our descendants will certainly not see Obama as a kind of American Messiah, but nor will he be seen as a kind of demonic force driving America to perdition. He is more likely to be seen as a kind of willing cog in the machine of the Zeitgeist. He will not be seen as a Chernabog, but more of an Eichmann; he willingly cooperated with evil, and bears responsibility for that, but the evil would have happened without his cooperation.
One way or another, it will take some time to reach a "verdict of history". It will require a generation with no emotional attachment to his presidency, whether positive or negative, with information on the long-term effects of Obama's choices, and (rarest of all) with the honesty to refuse to make him a cardboard figure for their own propagandistic dioramas. If you voted in the 2016 election, it is safe to say that you will not live to see that kind of dispassionate evaluation.