Who would be mad? Besides we all know it is going to happen.
1.Because Naruto will save Sasuke from his hatred.
2.Naruto needs more help fighting Madara, much less having Obito to fight also, because as far a I am concerned Naruto can defeat neither, and Sasuke is one of strongest ninja in the manga still left alive.
Simply
Madara>Naruto
Obito>Naruto
Madara and Obito>>>>>>>Naruto(overkill)
And if Sasuke does not turn this will be
Madara, Obito, and Sasuke>>>>>>>>>>>>>>> Naruto(overkill)
There's nothing to be mad about with Sasuke changing to good. At first I didn't want Sasuke going to Orochimaru and felt bad for him, but then I understood him. I knew he should go to Orochimaru and that one day he'll be back to being good again. But right now he's being manipulated by Obito.
I agree except he is not being manipulated by Obito, we also thought he was being manipulated by Orochimaru too remember? Sasuke has made it clear he is using Obito and knows Obito is using him.