
Originally Posted by
arus2001
You can't really rule out the possibility that Sasuke actually learned shit while under Orochimaru's hand. I mean, you gotta figure there was a reason why he wanted the body of a Sharingan user, and it's more than possible Sasuke realized the very reason for that desire during his training. Combine that knowledge with who knows what all he'd literally assimilated from him when Orochimaru finally decided to try and take over, and I'm not really surprised Itachi's "old hat" tricks didn't do much.
I personally don't recall Orochimaru getting his hand lopped off (Not that Oro's physical body taking damage really seems to matter much when he can barf up a new form), but if Itachi used Tsukiyomi to give himself the opening, it'd indirectly have Sasuke experiencing it twice. Besides, if Deidara could somehow do Sharingan resistance training, everyone else in the Narutoverse should arguably have the ability outside of it being some kind of weird bloodline limit he may've had, however unlikely.
If anything else, the conceit of genius could be a contributing factor. See Naruto vs Neji for that one.