Ah, I see you are from the "TOBI IS MADARA ARGH ARGH ARGH" team
It was obvious. Why would Kishi tease us for.. 2 years? Just to let us down in near future. That would be so unbeliebly boring and definetly not in Kishis style. He's known to suprise his fanbase. There had to be some twist in that plot.
The reason so many people were adamant about Madara being Tobi is because Kishi laid it on unbelievably thick as to giving us proof to why Tobi was Madara. Basically every single well-versed character in the Naruto universe admitted that only Madara could actually be Tobi. Yes, he gave a great number of reasons to believe that Tobi was not Madara, but the evidence supporting him being Madara was overwhelming compared to that. I honestly thought the chances were better that Tobi was indeed Madara rather than not and I'll admit that I was wrong (lol in fact I think I even posted that I would be the first to admit it) but don't act like it was easy to see Tobi was not Madara before this chapter.
Either way, the evidence is still overwhelming that Tobi, at the very least, was in close contact with Madara for the majority of his life. After some consideration, the only solution I can come up with is that Tobi is the orginal Zetsu and has basically become a clone of Madara. So in a way, Tobi is Madara, but he is not the real Madara. Since there is an Edo Madara, that means that the entirety of Madara's soul was in the pure world. That means that Tobi's soul/ consciousness is that of a different person. I can only suggest, based on this evidence, that Tobi is a Zetsu clone (or the orginal Zetsu) that possibly is using the body of an Uchiha, like Kagami for instance.
His abilities are something to think about though, his space time I mean, so perhaps he inherited some of Madara's tech from becoming a perfect clone essentially? Idk but I don't think it will be as simple as Tobi being Izuna, theres more to it.
I must say, I honestly did not care at all that we saw Edo Madara this chapter (in regard to being wrong about Tobi), the chapter was so unbelievably epic that I can't imagine any Naruto fan being disappointed by it. End of story.