Oh yeah, his summon. There we go. Problem solved to be relevant in this battle again. As for Sakura, trying to not get my hopes up but it will be smart for Kishi to surprise everyone by suggesting Sakura to summon a slug to attack Obito, only to have her go sage mode and Naruto will be shocked. Tobirama could comment on it as well. Wishful thinking but trying not to push it before Kishi may think, "Oh, he knows? Ok, time for rewrite!" Lol.
it could also be that Obito might need to change tactic. Naruto kinda showed that Obito can be beaten so we might get either some filler fights ( for me the fighting is all filler) or Obito has to counter Naruto's senjutsu with something else. And other than disapear into kamuiland ( where Kakashi is) I don't think Obito has any asspulling to do. The only possible one is for him to also get senjutsu but it feels out of character.
Now there's the yin Kyuubi who feels a bit out of place.Is he good is he bad.