Correction:
Madara -was- the Mizukage. [spoiler] The current Mizukage has been shown. And surprise! IT HAS BOOBS! Mizukage = a female. Madara is not a female. There for---swing and a miss. [/spoiler]
Also, things are not going as things planned for Madara simply because Akatsuki keeps being killed off by Naruto's influence and group. He's called Naruto a wrench in his plans and that he'd need to speed his plans up because of him. As well as I have a hard time believing Madara is powerful -now-. When Minato fought him, he couldn't match him up because of his use of the Sharingan. But nothing was said about his actual power.
If anything, his power revolves around using the Kyuubi as a weapon and when he does, he is seriously weakened to the point that he can't do any damage. Namely since his time gabs from being active at all are too long. After fighting the First Hokage with the Kyuubi, he vanished. Only to comeback and challange Minato. And then, come back once more, ten years later to have Itachi wipe out the Uchiha clan in exchange for sparing Konaha.
Madara's abilities as of now are completely unknown so he seems to be top tire, just as Pain was. Although, once they'd figure him out, I'm sure the idea that he's that far up will be shattered to some point.
As far as him being Danzo is concerned, Danzo shows nothing but a need to -rule- Konaha while Madara wanted to crush it period. If Madara was Danzo, he wouldn't have hid while Konaha was destroyed, or for that matter, killed the messanger Frog that was going to get Naruto and bring him to the village, he would have let it bring Naruto so Pain could have attempted to capture him.