What has Kishi got against Minato that he keeps having him mutilated?

Maybe Obito is going to steal Madara's half of the Kyuubi, fuse it with the one Zetsu has and then transfer it to Naruto. That would leave Naruto with a power up and with Madara potentially being screwed up from having swallowed Bee along with Hachibi.

The to even up the odds you would probably get a Sasuke/Kabuto combo, with support from Gaara, Kakashi, Guy and Lee.

The other Kage will probably just be useless.