I can't believe anyone would try to make an educated deduction of who is capable of possibly defeating Madara without knowing Madara's skill set. He has shown earth and Space type jutsu he was decent enough at Taijustu to kick Naruto back into the creek but he really hasn't shown his serious side for anyone to assume who could win. I would like to say Naruto but I would be silly in my guess even if I listed the many reasons why I think he could win from sage mode to everything between that and the will of fire in his repitoire. I would also like to say Sasuke because he is the only one with the Sharingan and KG to sustain the power and achieve EMS but he doesn't even have that yet.
Madara is an unkown and therefore semingly invincible until proven otherwise and soI like the thread but I can't make an educated guess. However there are some KIA shinobi that would dstroy Madara in his prime but if we don't count them I can't say with out sounding utterly rediculous.
technically not the point of the thread... from my understanding it is asking who'd probably stand most chance... from that i just speculated that a space time jutsu or amaterasu may be able to hurt him as the amaterasu sasuke used wasnt intentional otherwise madara could have been in more trouble...
this is a totally hypothetical question and i'm not taking into account madara's offensive capabilities merely who may actually be able to hit him.
and obviously who's best matched against madara for dead people im sure anyone would agree would be
a) sage of 6 paths as created the original jutsus
b) 1st hokage as he beat him once
c) minato who can move very quickly and stopped the 9 tails
bear in mind this is a purely hypothetical question and although most people on here doesn't know the meaning of the word education... some people actually can use their own intelligence to come up with a plausible answer rather than spouting off and dismissing it totally.