obito a certified dumbass used his MS right after awakening it no training or whatsoever,sasuke wouldn't do that?And to the people who are using the Sharingan as an excuse....why did Sasuke train with Oro? by this logic Sasuke with his 3 tome Sharingan didn't also need train with Oro, but that was not the case....Sharinga or MS or EMS doesn't make any different...you can't use it's power until you train with it.
plus sasuke said himself before kage summit he wanted to try something then suddenly out of nowhere he used susanoo,meaning he wasn't even sure he had susanoo!