Tobi stated that he intended to synchronise Sasuke with Gedo Mazo during his conversation with Zetsu following the Invasion of Pain arc. Now he didn't give any specifics, but the two most logical conclusions that could be made from this is that he either wanted Sasuke to cast the Mugen Tsukuyomi himself, in effect making him an accomplice to Akatsuki's actions, or he was intended to be exploited as a sacrifice for Madara's resurrection. That would explain Tobi's indecision about inserting the other Rinnegan eye into himself.
From the way Tobi reacted to Kabuto having reanimated Madara though, it's possible that his ulterior motivation was to never resurrect anyone. This is further validated by their fractional working relationship when controlling the Jubi. It begs the question of what the true purpose might have been for Sasuke in Tobi's mind. Did he just fancy Sasuke as another pawn that could be put to use for his aims? Or was there a deeper meaning to his interest and determination in seeing this vulnerable man plummet into the debased clutches of his own resentment and proclivity for violence? It could be that Tobi looked upon Sasuke as a protege. A youth who shares many qualities to himself whom he could relate to in a kindred sense.
A theory like this one was brought up some time ago actually. The conclusion was that Tobi's intentions for Sasuke never came to fruition like he wanted and now they're at opposite ends of the proverbial blade.
With all this reveals there's the possibility he wanted to use Sasuke to resurrect Rin. At one point if everything went to plan he could have accomplished that without much effort. Shisui's eye, the rinnegan eyes and probably the synch with the gedou mazou.
Shisui's eye for himself to mind control Sasuke, and the other 2 to give sasuke the power to resurrect Rin. As for the bijuu and war and everything probably to get revenge or try to make a world of peace... but let's be honest Obito's only motivation is Rin. And even if he didn't had Shisui's eye he could still accomplish something by planting a Zetsu into Sasuke and forcing him to use rinne tensei.
The thing about Obito and Sasuke and Naruto is that it's similar to what hapened with the sage and the 2 sons. Only this time the relationships are twisted. Obito and Sasuke share the same goal ( to gain power in order to bring peace). Also Obito's actions have helped shape Sasuke and Naruto. Naruto became an orphan because of Obito and Sasuke was pushed to the darkness with a little help from Obito. I think we won't see a Naruto sage of the six paths anymore except for when he will split the bijuus back in to 9 ( or 10?). Even if he isn't the sage he has inherited his will and will guide the tailed beasts. Anyway if Naruto manages to TNJ Obito and Obito will be redeemed eventually he will side with the younger son.