Well, not late this time.
Before getting to the backstory, I should address the way on where this is going. The fact the sneak attack didn't work and they have to sort to that jutsu now in chapter 2 of the combat and Hokages haven't show up goes to show you that this will not last long and all will participate. I demand a new Naruto's drink if I am totally correct. Lastly, the idea that we see other Naruto doing the work and recently taking Obito tell you that the main event is being setup because why is it significant to see Naruto saving Obito, let alone actually saving him. It's not like Naruto or Sasuke was about to crash to that same spot, so pretty much this is saying, "Hey, I'm gathering all of them to prepare the real fight that warranted a badass soundtrack or final collision soundtrack like Final Fantasy final boss." In other words, it's coming.
Now, to the back! Well, this explain many questions in the past. I thought Hagoromo did a mistake by making that tablet, which probably said don't ever do the moon eye plan, but Zetsu did it to make it seem like it's the answer to life. Sadly, no one took the bait, so Zetsu waited for days, that turned into months, that turned into years. It sounds like a sad story if he was a good guy. So his best shot was Madara, but he failed. Luckily, Madara was a genius, so hope rejuvenated. Once he got the eyes and able to summon Gedou Mazou, then he can finally start his greatest dream: Kaguya's resurrection. It also explain Hashirama, which probably the reason why it later turned into a full body flesh. Madara did adjustment, so stuff like him living long as well as alternating Zetsu, so this is explained. The way Black Zetsu was designed to wait for a long time seems like an indie game story with a spooky atmosphere like Limbo or that new game Inside. It has that feeling in a strange way. But again, he's a bad guy, so yeah. This covered the Madara's plotline since the day of defeat by Hashirama. It even explained Kabuto because one would think, "How did he get that body?" I know many of us were confused and find it hard to believe that either Orochimaru found it a long time ago, which would be dumb because why no edo tensei on it long time ago, or Kabuto just got lucky out of the blue, alas plot convenience. As for the explanation on Kaguya's disappearance, well that seems to be on hold for her to tell the story, because Black Zetsu filled in the plan in the making, but now, we need to know her downfall, especially being sealed by her own sons. It does sound messed up. If she were to tell her story to people without killing them, she will be the victim and we will hate her sons. It sounds like it may end up the similar way of Halo 4 backstory on Didact.
Now, the ending of the chapter pretty much escalated quickly on Naruto and Sasuke only show, so good for many of people here. Happening too soon only suggest it will work but not enough or it didn't work. Thankfully, those Hokages really give you an impression that this upcoming chapter won't end the fight at all. Unless Kishi just want them to cheer, but I strongly doubt them. To me, they will add a lot of reinforcement as well as making all in field (maybe not Obito...yet) meaningful. In due time. Patience, my friend.
P.S. Lol at Sasuke. Who shining more now!