Hello there, random person on the internet, I'm here to discuss a little theory I thought up a few days ago. I think that Madara is not in his final form yet. First, his staff is incomplete as seen here:
We'll get back to the staff in a little bit. Secondly, Madara appears physically different than Obito's Jinchuriki form in multiple ways, but strongly resembles the Six Paths Sage. Now here's the real kicker, what has Obito gone through in his Juubi Jinchuriki phase that Madara hasn't?
That's right, Madara has yet to have an inner conflict with the Juubi him/herself! I believe that the reason Madara stole sage mode is not necessarily to gain an immunity to senjutsu assaults or to become stronger, but it is to pacify the Juubi, which means he has not yet left the first stage of being an Juubi Jin. Also, this is for reasons of interest to the plot, as it can potentially set up an final conflict with the Juubi and Naruto once Madara's senjutsu chakra runs out. This phase Madara is in, resembles the sage less closely than Obito's did, which denotes that he is still in an inferior state. Lastly, the staff Madara has is incomplete, although this may be pure speculation, I believe that the staff is a visual indicator that someone has achieved an perfect jinchuriki (phase 2) state of the Juubi.
TLDR Version:
You must be registered for see images
You must be registered for see images
You must be registered for see images
You must be registered for see images
TLDR Version:
You must be registered for see images