In my opinion, Itachi really could have surpassed Madara. Madara at a young age was incredibly powerful, he was around the age of part 1 Naruto and already able to defeat the older and stronger members of the Senju Clan. Itachi was incredibly powerful too, however. He already became an Anbu captain at age 13 which is just outrageous. Madara got as strong as he did because of his EMS, otherwise he would've gone blind and become fodder who couldn't fight anymore. If Itachi had gotten the EMS, I'm confident that he had the ability to evolve it into a perfect susanoo. Pre-Tinnegan Madara is in an entirely different tier than edo-Madara and beyond, so I want to make sure there's no confusion; I think that Itachi would have surpassed Madara with no Rinnegan, had Itachi gained the EMS