I agree itachi in the state that he was when he fought sasuke, isnt enough to defeat kabuto. He will trouble kabuto no doubt but kabuto would prevail. However im a firm believer that edo itachi would beat him.
Anyway first and foremost i can never understand those who say if itachi wasnt edo he would be long dead. First of all the reason why kishi allowed itachi to take those hits is because he is edo, he was using itachi's edo abilities to its fullest. If it was living itachi vs kabuto, kishi wouldve altered the fight.
Secondly other factors such as the purpose of the fight.
Itachi taking advantage of his edo form
Protecting sasuke
Activation of izanami
All these factors were what allowed kabuto to damage itachi. I keep on hearing people say both parties were not fighting to kill and this is true but its more than that, never once was an attack by the uchiha bro's aimed at kabuto, they were defending their ground from the very start. Itachi made it very clear and still repeated it several times to sasuke that, they cannot attack kabuto. The only real attack from the bro's was for the activation of izanami where kabuto made contact with itachi's karasu bunshin. That was the only attack aimed at kabuto and that in itself was a decoy for the purpose of the fight.
Kabuto intentions was also to take control of itachi, but also keep sasuke alive for his own goals, he didnt attack sasuke. He did however attack itachi. Sure his aim was to take control of itachi. But in order to either seal or take control of an edo, they have to be severely damaged and that was what kabuto did. Attacks ranging from;
Senpo Muki Tensei
Senpo Hakugeki no Jutsu
Sawarabi no Mai
Mateki Mugen Onsa
Doton Doroku Gaeshi
Kumosokai
Chakura no Mesu
Are techniques that were aimed at itachi. Kabuto had to have him damaged in order to regain control of him. What im saying is that whether kabuto's aim was to regain control of itachi or not, he had to have him severely damaged in order to do so therefore whether kabuto's aim was to kill or regain control of itachi is irrelevant because its these same attacks that he would've used if the fight was to kill and itachi was alive and not edo. Whilst ive come up with a list of attacks that kabuto aimed at itachi, i wonder whether somebody can come up with a list of attacks that itachi or the bro's aimed at kabuto, apart from the karasu bunshin which was to activate izanami.
Kabuto's fighting style wouldnt have changed, because its these same technique's he wouldve used. Itachi's frame of mind and thinking strategy wouldve changed and he might actually decide to find a way to defeat him even with the abilities that kabuto has gained. Perhaps decide to wield the legendary weapons himself, which wouldve made him a very dangerous opponent with the speed, taijutsu and precognition feat thanks to the sharingan to use these weapons very effectively, not even kabuto's medic ninjutsu prowess would save him once the sword has pierced him.
As for the sound genjutsu i personally believe people are trolling when they say itachi or the brothers were there for the taking and if neither had a partner that was that for them. That genjutsu was broken by shikamaru in part 1 inflicting pain on himself. He did this by breaking his finger. To say either genjutsu users who have shown such feats to genjutsu cannot do the same or something similar is beyond me. Itachi was in his edo state and couldve decided to do exactly what shikamaru did, he wouldve regenerated his finger. Instead i believe he took advantage of this scenario and decided to do what he hasnt done all his life which was to recognise his comrades abilities, especially sasuke's who he has constantly been sleeping on
