Hmm, the first time he got caught in Genjutsu, but now he knows how to repel it.
No, he doesn't know how to repel it now.
The second time he got partially sealed by Totsuka because he thought it was a normal sword. Now it's not happening thanks to knowledge.
No. Knowledge doesn't automatically safe his ass, he's not immune to it.
Parasite and Shadow Clones render Tsukuyomi useless, since a failed shot means a massive chakra drain for Itachi.
No, Tsukuyomi means a lot of Chakra costs if it actually had success. If Tsukuyomi has no success, it won't cost Chakra. Clones are no counter, they work as a feint once, but are never a counter to get rid of powerful techniques. Counter means, you are able to avoid the technique in a direct confrontation. That's not the case for Orochimaru. Bunshin feints and avoiding eye contact is a cheap argumentation. Itachi could counter anything Orochimaru tries with Bunshin as well.
Upkeeping Susano'o is useless since Zetsu Orochimaru can outlast Itachi like thousand times. Itachi has no counter to multiple Mayfly+Kusanagi snipes from beneath the ground, since Mayfly is confirmed to be undetectable by any sensory mechanisms.
Susanoo isn't even needed for Orochimaru. If he pulls out Susanoo, it comes to an end anyway, as Orochimaru can't dodge Susanoo's attacks in the long run. Means, Totsuka blitzes him.
Also, Itachi has no way to counter Oro's swarm attacks. 3 Ribbon/Cursed Seal Snakes + Twin Snakes, Formation of Ten Thousand Snakes and more followed by sneak attacks with clones or using his transportation methods are more than enough to overwhelm Itachi.
I'm familiar with Orochimaru's techniques. Your thoughts of this battle are too complicated. Orochimaru already admitted inferiority to Itachi 10 years after their encounter. Means, that Orochimaru's tricks won't work against someone who's battle skills are far beyond himself. Itachi will always be one step ahead.
Rιver said:
So you argument is; ''He made himself immune, but wait, I have nothing to prove that''. Clearly, Orochimaru is still the old fart who got schooled by Itachi - twice.
This. Things will never change. Orochimaru will only dream about having Uchiha powers.