Tobi switching bodies can be a possibility but he can never be Obito or using Obito's body IMO.That is true but if he is switching bodies he may be using the same Jutsu as Orochimaru did so who knows how many different bodies he's actually had the body he used vs the 4th may not be the same body he is using now & that maybe why he is getting Sasuke as powerful as possible so he can get his body as well
I dont understand why everyone is making big fuss about Obito. There were lot of sharingan users back then and Obito was just a normal kid who only awoke his sharingan right before his death. End of chapter.
I think Tobi is either Madara or his brother due to following reasons:
- He must be an Uchiha - because he always brag about the power of Uchiha and how only Uchiha can fully master the Sharigan eye(s) etc.
- He always talks about how much he admired Hashirama and blah blah.
- As Naruto's mom explained during Madara vs Hashirama fight Hashirama gained control of the Nine-Tails which means Madara summoned the Nine-Tails to fight Hashirama. - When Tobi was fighting Yondaime he easily summoned the Nine-Tails like his pet.
- He knows a lot like the history of SO6P, the tablet, when jinchuuriki's seal is at its weakest etc. - which means he must have alive when Hashirama's wife (Mito) gave birth or something.