This logic is flawed. They'd have an advantage with only the first pair that they target, but after that it will be uphill for them because Akatsuki at that point will know about their plan and have Zetsu spie on them.zetsu can find people from anywhere on the earth, so they'd be the ones getting surprise attacked from then on, and they'd become the prey instead of the hunters that they began as. Also, there are some guys who are immune to Itachi's genjutsu in Akatsuki, such as Deidara (trained his eye for years to see through genjutsu) and Sasori (puppet body, no real eyes for eye contact), Kakuzu potentially is immune to genjutsu as well because he has five interconnecting chakra systems (hearts), plus his montsers can fight independent of his will as we saw them fight and move around even when he was temporarily dead. The masks could break him and Hidan out of genjutsu as well. Black and White Zetsu together should theoretically be immune to genjutsu, because they are two in one and therefore two different chakra networks and minds, I see them being able to break each other out and Tobi and Nagato it goes without saying that visual gen is useless on them. So you see, each team actually has a guy that can defend against Itachi's greatest asset, Kisame and Samehada are also in this debate. So you see, it wouldn't be that easy. Amateresu might be a problem under normal circumstances, but just as much as Oro and Itachi have intel on Akatsuki, so do Akatsuki on them, I'm sure everyone in Akatsuki has thought of ways to defend against each member should things go south, so the battles would be hard fought. It really wouldn't be easy for anyone. Though Yata Mirror would be an incredible asset for Itachi, and maybe Oro and Kabuto would find a cure for his illness too, so daym, this would be epic. Edo Tensei is also an Issue. Can Edo regenerate from complete disintergration? As in, can Edo's come back to existence after C4? Can Yata Mirror and Totsuka remain active without chakra? As in, can Samehada, Great Water Shark Bullet, and Preta Path rob Itachi of these weapons by absorbing the chakra that manifests/summons/maintains them? Can Yata defend attacks from underground? Would Itachi get Hashi dna tranplant from Oro? Etc etc. Too much to consider honestly. It seems like even if Oro and Itachi lost, both sides would lose alot, Akatsuki would probably cease to exist even after winning, unless maybe if they recruit younglings like Jugo, Karin, and Suigetsu and personally train them, otherwise Oro and Itachi would succeed regardless of whether they ended up dying or not.
