The upcoming filler will be great in the "development" of his character. We all know that the dreams will involve the user facing their fears and ultimately winning and ending in true happiness.
This will either make fans of the anime hate him even more (Because this is all a dream and he is playing them like a fiddle) or make them love him (because he is giving them peace of mind [like what happened to Yamato]).
So when he gets stabbed in the back (pun intended), it will be even greater for those who hated him. Or it will set up Kaguya in a better manner because people won't really see Madara as the ultimate "bad" guy. She'll be considered more evil and a more "appropriate" final villain.
This will either make fans of the anime hate him even more (Because this is all a dream and he is playing them like a fiddle) or make them love him (because he is giving them peace of mind [like what happened to Yamato]).
So when he gets stabbed in the back (pun intended), it will be even greater for those who hated him. Or it will set up Kaguya in a better manner because people won't really see Madara as the ultimate "bad" guy. She'll be considered more evil and a more "appropriate" final villain.