Most Kage would be dead. First soloing A, then taking on Gaara, killing Mei in the room he was caged in with her and then, probably Oonoki would have died by him using Amaterasu before Oonoki releases his Jinton technique. As the EMS reduces the drain of your chakra, he would've literally faced Danzo with his full strength and on a stronger scale than back then.
The plot actually wouldn't allow Sasuke to kill them all, but with the power he displayed and the Kage being separated from each other, which in result made them facing Sasuke respectively alone, he could've achieved this.