In terms of power, easily. However, Kaguya has fought like an idiot throughout the fight, relying on Zetsu to help her. Madara is a seasoned warrior who loves to fight. He would stand a far better chance than Naruto or Sasuke did, and Naruto did pretty well on his own. I'm not that much of a Madara fan, but I recognize what a great fighter he is, and with the power he has, he would have been able to overwhelm even Naruto and Sasuke, and it took both of them to overwhelm Madara.
Plot shield made Kaguya dumb and incompetent, but plot shield also gave Madara inability to kill people. He could have killed those kage easily, and he could have dealt great damage to Naruto and Sasuke, which he did before their powerup, when he wasn't even close to full strength. I don't think Madara is more powerful than Kaguya, but he would still beat her because he's a powerful, experienced warrior.
His main downside is that he loves to fight and show off, I guess. When he didn't want to fight the kage anymore, down they went.