Lincoln was not that great of a human, actually. As others have said, the Emancipation Proclamation was not a catch-all end-slavery action. First of all, it did not free slaves in the 4 border states (states with slavery that were on the Union side). Secondly, it was not a humanitarian action, but was intended to cripple the Southern economy. Thirdly, this weak freedom came more than 50 years after Britain had already banned slavery, and this Proclamation did nothing to stop persecution against blacks through means other than slavery.
No, probably the greatest American ever was MLK Jr, with Andrew Jackson being the most badass (sorry, Teddy, but you didn't have a parrot that cursed your own cabinet members. And you didn't beat the first attempted presidential assassin so hard with your cane your bodyguards had to pull you off. And built a statue of yourself at the site years later) and Admiral Alfred Thayer Mahan being the most influential (despite most of America not knowing who the fuck he is).
Worldwide... I would put the greatest human ever as Nelson Mandela. Just because.
No, probably the greatest American ever was MLK Jr, with Andrew Jackson being the most badass (sorry, Teddy, but you didn't have a parrot that cursed your own cabinet members. And you didn't beat the first attempted presidential assassin so hard with your cane your bodyguards had to pull you off. And built a statue of yourself at the site years later) and Admiral Alfred Thayer Mahan being the most influential (despite most of America not knowing who the fuck he is).
Worldwide... I would put the greatest human ever as Nelson Mandela. Just because.