Board Thread:Theories and Speculation/@comment-33953813-20171226015659/@comment-28819877-20180103223149

Thekillman wrote: Besides, it's about what Madara would've planned, not about what BZ actually intended. BZ was fast enough to outplay Minato, and stealthy enough to mislead and backstab Madara. Obito would not have much choice in this whole affair, if BZ would chose to supplant Obito with Madara.

The thing is it`s unknown whether BZ wanted to use anybody who was able to cast IT (i.e Obito) or not, even if he originally had been considering Madara as a major candidate. And if he did, then Madara should have defeated Obito without BZ assisstance which would eventually lead Madara to death.