My theory is Madara knew BZ was manipulating the shinobi universe and that he's done all this in order to be alive and stop him. In other words he's faking his own death so he can eat Kaguya from the inside out and then eat the fruit. His goal is to save humanity and end the cycle of hatred caused by BZ.
Ultimately Madara sees ninshuu and ninjutsu as the reason shinobi suffer, so he wants to concentrate all power into one person (himself) and destroy the entire idea of ninja, by killing Kaguya and her family, sealing the Juubi forever and saving the world from a pretty bad fate of being Infinite Tsukyomi fodder.
Won't happen. Madara, if he came back somehow, would be expected to be good. He would have heard the story from BZ and will be contrite, feeling played. He will be drained, old, and will die asking Hashirama's forgiveness. Anything else would be inconsistent.
I don't think Kishi should bring him back, though. Assume he was killed off and move on. The real impact is now suckske knows that his entire path was wrong and he has been playing into the hands of BZ. But his character is arrogant beyond measure, so their is still an opening for Kishi to have him continue to act like he knows better than the rest of NV.
Also don't forget the original rationale for Kaguya eating the fruit and taking control was to stop all the wars. Removing chakra, ninnshiu, and ninjutsu would not end wars. So that plot line would achieve nothing.