i would think that the reason why obito is doing all of this is beacuse kakashi didn't protect Rin. I would think a mastermind would need more motivation than that:shrug: ........
I Thought Obito was at piece with his decision to entrust Kakashi and give him his sharingan. he said it was unfortunate that he couldn't have stayed longer with kakashi now that they had developed a friendship. He also said that he regretted not expressing how he felt about Rin. I always thought that Obito's sacrifice helped change Kakashi's ways, because of obito's sacrifice kakashi learned that teammates are more important than the mission. Just because Kakashi could not keep his promise seems like a pretty silly reason to want to cast the world under ultimate tyskyomi.
Who knows? It should be an interesting explanation once we get more info. I have a feeling we are going to switch back to the other fights going on for awhile to let us "stew" over the new info we do have.