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 considered Madara as a major candidate. And if he did, then Madara should have been defeated Obito himself without BZ assisstance which would lead Madara to death despite his arrogant nature.