I dont know griffnat excuses. But for me Kaguya arc got to many asspull and plot nerfed and it became a joke. I hope that arc can be good and if Kishi decided to kill Madara that way, he should redeem what he did to Madara by giving/managed Kaguya properly but I'm very disappointed with the result.
It's actually a joke cause near about 80% of Kaguya Arc Haters are Rustled Madara Fans cause Black Zetsu negged thier fav, i.e; Madara. Lol
Kishi managed Kaguya very well. First we saw her imbalanced personality, sometimes Crying, sometimes full of hate which perhaps hinted that Kaguya was being controlled by a much more evil force. Moreover Kaguya also didn't have a heart, her humanity was completely destroyed as Naruto and Hagoromo stated.
Madara was not redeemed properly but that's because he still has a role in Part 3, I think you remember that his Rinnegan can summon Gedo Mazou and his body is a perfect vessel for Orochimaru. Madara had a conversation with Hashirama and he did die in peace, but he was not able to complete his sentence. What does this show ?
It shows that the ending of both Madara and Kaguya's plots are vague. I think Kishi did this intentionally to develop them in Part 3.
Yeah I wont deny that was lame.He could easily have switched to a limbo clone.Anyways I think Naruto and Sasuke would have still owned him at some point later with their powerups
For all intents and Purposes, both Madara and Obito (If he stayed evil) became irrelevant once Mugen Tsukuyomi was casted. From there Kishi had two Options : Make Naruto and Sasuke win (Cliche and Lame) or Make Naruto and Sasuke Lose and make them fall in Mugen Tsukuyomi (While this is a valid option, it would make the plot very complicated).
By bringing in the Kaguya plotline, Kishi brought a superb twist in the manga and prevented it from becoming a lame circus show.