This is what everyone believed. Everyone thought that the Masked Man was Madara Uchiha with an exception of Zetsu.
This is a confirmed fact.

Madara's Plan was to get Obito to capture all the Tailed Beasts and summon Juubi. Then Nagato will revive Madara with Rinne Tensei, Madara becomes the Jinchuuruki of the Ten Tails, then he casts the Infinte Tsuky No Me.

This plan was flawed but makes sense and is plausible with an exception of one part and this is arguably the most important part - Nagato revives Madara.

Obito was masked and was acting under the name of Madara and Nagato believed this. Was Obito going to reveal himself to be an imposter? If not, why would Nagato revive someone he 'knows' to be alive?

Adding to this, Nagato and Obito had differing plans involving the Tailed Beasts. Obito had the Eye of the Moon plan, Nagato had the quell fear and pain into the ninja world and both wanted to create utopia.

Obito would at one point have to confess the new plan - Nagato would not react lightly and a fight might commence. Obito is stronger than Nagato but it would be difficult for a single person to fight against the Six Paths of Pain.

Anyways, to Nagato, Madara was still alive so how would Madara's plan be fufilled? Unless of course, Obito was never planning on reviving him. :3

What do you think? Plot Hole or a Hint to the Future of Obito/Madara plan?