Perhaps he cannot use the Rinnegan like Nagato can. Madara's Rinnegan seems to be an advanced form of the EMS which only purpose (speculatively for now) is to summon the perfect Susanoo. As to if the Rinnegan is requred to make Susanoo perfect is debated, I think it is, but who knows.
It's like Itachi giving his MS powers to Sasuke. Sasuke can't use Tsukyomi as well as Itachi and Itachi can't use Blaze Release Amaterasu as well as Sasuke.
That is, if Madara did give his eyes to Nagato. But that's a whole'nother argument/debate...