A big misconception alot of people assume is that madara received some big upgrade from absorbing the shinju, He might've gotten a better regeneration power but that's an assumption.
I'll explain the true purpose of absorbing the tree
You must be registered for see links
(You can read it or not)
Also he's missing yin kurama which is a big difference in power since yang kurama overpowered five bijuus.
Second reason: madara doesn't have as much experience as rikudou has being a Jin.
Madara was jin for what, An hour? Rikudou was a juubi jin for decades up until he died.
Another reason why madara will lose, Is because two halfs of base rikudou's power gave one eye'd rinnegan madara huge trouble to the point where he desperately needed to get his other rinnegan back. Juubi jin rikudou would mid diff madara.....