Yea I agree even if Obito was killed Madara could've possessed someone else with Black Zetsu. Black Zetsu with one rinnengan would've forced someone to cast rinne tense
It would have been bittersweet as I believe Obito should have died near that moment but a death like that after giving in to the tug of war would have been terrible. I wanted Obito to kill Kakashi in the kamui dimension instead and then Naruto and Sasuke should have killed Obito.
maybe naruto would be dead now, or naruto would have gotten the other half of the kyuubi without getting the 1 and 8 tail's chakra. so good thing it didn't happen.