Well,let's see.Kabuto revived Madara with edo tensei and he really has a big role in this:He destroyed the 5 kages,and is going to help Obito with the project.But:

If Madara wasn't revived,Obito would be in an impossible situation:fighting naruto,kakashi,bee,gai + 5 kages,and ofcourse he would have died and lost the war.But he was annoyed when he saw Madara in that coffin,thinking that he has surpassed him and could take this war easily.He has to realise that without Madara he would be doomed.

But all started from Kabuto,so he should be gratefull to him.

Any thoughts?