You can't compare Sasuke vs 5 Kage to Madara vs 5 Kage.
1) Only 3 of 5 Kage were fighting Sasuke to which they only failed because someone intervened
Ay could have easily smashed Sasuke if he didn't activate Susanoo but even then, Sasuke still got injured.
2) If Madara wasn't an Edo Tensei, the 5 Kage would have smashed his ***** ass like the fodder he is. It's only due to his regenerative capabilities that he's still alive and well, hell even a Kyuubi Enhanced Lee deuced him with 1 kick.
3) The Kage weren't even putting in much effort save for Ay who went full power due to wanting to obliterate Sasuke (I mean who would show mercy against someone who killed your brother), if they went full power Sasuke would've been dead.
4) Old Sasuke, new Sasuke, it doesn't matter. He hardly got any new power-ups since the kage summit, only a new MS design and better enton control. Big Deal. Oonoki is enough to wipe him out, low-diff.
Sasuke may be Kage-Level, but he isn't powerful enough to take on the Kage. Can't even take on Ay himself. He goes in as if he's a badass, then gets saved 3 times like the bee-i-itch he is.