If any it's black zetsu stabbing madara lol. these so called ''ass pulls'' hardly exist or its for people to bash the series. kakashi's susano'o was no ass pull and made PERFECT susano'o sense because Obito the original owner of the power, gave his UCHIHA CHAKRA and he kinda became the jinjurhiki of kakashi hahahaha if that makes sense. Just like how Kurama lends Naruto his kyuubi powers, Obito lends kakashi his MS powers. Though obito by his own will decided to be inside kakashi (no homo) where as kurama by force was sealed within Naruto. If kakashi had both MS by transplant then OBVIOUSLY he couldn't handle the power let alone go susano'o. when obito left kakashi's body, kakashi had become extremely weakened, just like a jinjurhiki is near death when his/her bijuu is extracted from their body but Obito's chakra is obviously not as huge as a bijuu therefore kakashi can survive. This is what i believe lol.