i dont know that obama is letting the wars linger. I think he's keeping the bases there because, well, only people who have sex with donkeys still deny the wars were about bases and oil.
But as far as killing all the MFing bad guys - well, he's doing it. Our troops will 'be there' for decades, but the fighting will be done quickly. he left iraq and after the surge we'll end battle in afghanistan (although always keep the bases- see: people who have sex with donkeys for alternate belief)