There’s a high probability of this happening in the upcoming chapters. Obviously, Obito sees himself in Naruto (which has been hinted at earlier), and usually when such a thing happens, Naruto manages to successfully persuade said person. Although; the biggest reason seems to be Madara not wanting to start the ritual immediately as opposed to Obito —which seemingly indicates Madara “true” motives for the Moon Eye Plan.
Madara does not seem the least bit concerned in the Moon Eye Plan that he told Obito about, instead it seems like he simply exhausted Obito as a means to attain power all along? If this is the case, and if Obito did suspect such a scheme, than it would explain Obito’s unenthused reaction when Kabuto resurrected Madara through Edo Tensei.
Looking at Madara, his plan is the opposite of what he has been talking about since his introduction. Firstly, he preaches to Obito about a world that abolishes winners and losers, and endorses peace and love: however; he places his competition with Hashirama above all. Why would this be important to Madara if he is creating a world that eliminates this very aspect? Secondly, Madara finds pleasure in fighting and seemingly remembering his war-filled past. These recollections could be Madara’s “ideal world,” a world where his past is the norm, and in this world he is the undisputed champion.
This could obviously cause a fallout between the two Uchiha's. Leading to Obito supporting Kakashi and Naruto against Madara...
This is eminent; the author has been regurgitating the importance of both Sharingan eyes and the teamwork between Obito and Kakashi for several preceding chapters. For many reasons, I do not think that Obito’s final Mangekyō technique will be Susano’o, but it is a probability. Instead Obito’s final Mangekyō Sharingan ability may be either of the following:(his Susano’o if he has one, could use the listed abilities as a weapon)
1.) Warp huge areas, around themselves and afar to the other dimension.
2.) A strengthen Kamui ability predicated by the unlocked combination of twisting or condensing the space around that person, and the space around that space. Thus, resulting in a form of time traveling, where the user bends space around space, around himself and/or an object(s) through the Kamui dimensions recycling events or fast-forwarding them.
The alliance successfully defeats Madara with Obito's help.
As presumed Obito, it was a success...