*Madara heals faster than that. Remember when he lost his arm. He would have healed already if he could.
*Why in the world would Madara return stronger than ever after healing from his legs? That doesn't magically create more chakra.
*Madara cannot get any stronger since he has been confirmed to have reached his cap. Kaguya's chakra is above ten-tails and Six Paths mode and was too much for Madara to handle, hence why he bloated up and exploded. The Madara that got his ass handed to him by Kaguya was his absolute peak.
*Madara's purpose to the story is over and he was manipulated. He is either dead or will return and get the Piccolo treatment, AKA he will return as the protagonist's *****.