There is no way the alliance can match Juubi + Madara + Obito....
Even if Kurama and Hachibi recreates their chakra.... The Juubi is still stronger than Kyuubi + Hachibi.... there were no match no matter how you look at it....
Sasuke could be a savior right now.... but even with him i dont feel like it's enough.
I honestly see Obito turning his back on Madara eventually BUT faillng nonetheless..... but he would goudge one way or an other Madara's plan and actions and would also remove himself from the equation.... making it easier for Naruto co. to fight as Obito is a powerhouse himself.
Then i could see Sasuke and Naruto vs Madara.
Imo, either Obito will turn ''good' by learning that Rin's death was Madara's plan or simply by realising that Madara never wanted to create the new world but rather wanted to become the Juubi's jinchuriki only to become the strongest being to have ever existed.