Examples:
Could have pretty much taken out the entire akatsuki by himself
Could have just killed Kabuto and run around totsuka blitzing the other edos that were left, and defeating obito afterwards when he was an edo tensei
Was given a disease that decreased his stamina heavily, which made it his only weakness
If not Itachi is, then tell me who you think is and for what reasons.
No he couldn't have taken out Akatsuki easily, Zetsu was always watching everyone and reporting to Nagato and Obito so if Itachi tried to kill Kisame then he will be hunted down by Akatsuki and killed. He can used 4 MS jutsus and each ghost a lot of chakra and cause him pain and that hesitation can cost him.
And Kabuto could have just ended Edo Tensei to neg Edo Itachi but plot deem he didn't. Kabuto only forced his way in the war to get Sasuke and Sasuke was right infront of him so he could have easily coffin Edo Madara, Edo Kimimaru, and Edo Chiyo then end Edo Tensei and at the start of the fight Kabuto was dodging all Attacks with his sensory ability so no it wouldn't have ended the moment Itachi got there. Itachi isn't beating Edo Madara and Edo Kimimaru and Edi Chiyo team won't be that easy either. Edo Itachi would use up all his chakra before being able to seal Madara or Kimimaru team who have Chiyo who can control bodies and Kimimaru can make bones come out from right under you and all over the battlefield as he did against Gaara then move inside them. Edo Itachi have less chakra than alive Itachi and it doesn't instantly refill as it took Edo Minato time to replenish his chakra.
His other weakness being his MS which cost a lot of chakra per jutsu, caused him to go blind the moment he awakened MS and makes him blind faster when he uses MS jutsus (as Sasuke did), cause him physical pain after using MS jutsus (Susanoo takes both eyes and does more pain as it aches every cell in the body as Sasuke put it).
Madara was nerfed more after he became Juubi Jin lol they took away his Susanoo which he used pre-JJ with 1 eye, no wood clones, no wood jutsus, no katon jutsus, no Rinnegan jutsus such as Deva path, Asura path, Animal path, or Pretha path, had 5 of his TSBs FTG to Konoha. Naruto was nerfed a lot as well but the Madara thing was annoying since why give him the Juubi then not make him use jutsus he shown to use?