This isn't DBZ where next villain has to be stronger than the last one...
Madara with his max. powers faced whole world with 2 Demi-Gods... He was powerful beyond imagination, only reason he went out w/o going all-out was because unlike Kaguya, he'd have killed both of'em for sure...
Sasuke might have gotten a little hold of his Sharinnegan, but still he ain't winning against Madara anytime soon...
P.S. As a matter of fact, Sasuke thinks his war experience is enough go against Naruto... Well, he's wrong, Naruto also learned from this war and should be nerfed to make this fight interesting...