it's not his ultimate weakness lol sasuke won because oro was on his death bed...sharingan was used because it was sasuke...simple as that. how else would he try to get out of sharingan? who hasn't fought itachi and fell under a sharingan genjutsu? just because they naturally use sharingan doesn't make it oro's only weakness if they HAD to use it against him. which shinobi at the time would be able to move in ITACHI'S paralyzing genjutsu? it's not the fact that oro got caught in it, as would anyone else. it's the fact that he was able to move, a feat in which even itachi noted. because sasuke was under itachi's sharingan genjutsu doesn't make it his weakness, does it? um no. if tsunade's hand got cut off from sharingan, does that make it her weakness? no. it's just a tech that both sasuke and itachi happened to use, a tech that would subdue most anyone. in the term "weakness" that you and mostly everyone else use when in conjunction with oro is the wrong "weakness". True Oro's weakness (an object of special desire) is indeed, the sharingan. just because the only person who happened to defeat him once (under fair circcumstances) used the sharingan doesn't make it his weakness.
in all, orochimaru didn't have many weaknesses at all. his main weakness is his arrogance. not the sharingan. itachi did not use sharingan to seal oro, fyi. Until Madara showcases any sealing techs that could seal oro, as far as it matters, it doesn't count. simply because of IF...
Too many invalid statements in your post dude, but I'm gonna point out what I understood from it.
First of all, when I said Sasuke has beaten Orochimaru, my point is that Orochimaru dragged Sasuke into the place of where Orochimaru should be under a full control, yet.. Sasuke countered his Jutsu and told him that anything he does is useless against the Sharingan, and Orochimaru was weakened as a human shape (a human body..), but he came out as a huge snake which is his true form, the snake itself wasn't weakened cause it's his true self, so the technique is not a weakened version or something, that's what I meant when I said Sasuke has beaten him, beaten him on that particular Jutsu/place of where he should be under a full control over anyone.
Now, you seem to mix up between Itachi's typical illusion techniques and the paralyzing ones, they are kinda different, but both fall into the same category which is (Genjutsu), the difference between the paralyzing ones and the typical ones is that the paralyzing would freeze the enemy and make them do simply nothing, they would be in a standing still situation unable to move but conscious and fully aware of what's going on, we still didn't see any paralyzing Genjutsu used by Itachi on any other Shinobi other than Orochimaru, also remember.. it is a normal Sharingan paralyzing Genjutsu, and not a MS paralyzing Genjutsu like the one Madara used on the 4th Raikage, if itachi used his MS paralyzing Genjutsu on Orochimaru he would have fall helplessly into the ground, that's why you saw him moving/resisting a bit.
And so what if he moved his hand during the paralyzing Genjutsu? think of it like the Shadow Imitation Technique Shikamaru uses, it simply binds you to the ground and makes you unable to move, I'm not comparing the two Jutsu's, but just giving you an example of how the paralyzing Genjutsu works.
Orochimaru simply wanted to use hand seals to release the Genjutsu, Itachi knew he'd do that, so he cut off his hand.. I don't see how that can be considered as a unique thing for Orochimaru by just moving his hands a bit, once again.. the Genjutsu was meant to paralyze Orochimaru's movement, different than the typical ones Itachi uses, like the crows etc..
Also to note you on something:
You must be registered for see links
Here, you can also see that the spikes are driven through Orochimaru's body while the hands are not touched, this might also explain why he was able to move his hands.
Also, Itachi used the Totsuka Sword to seal Orochimaru.. Susanoo was required, and you can't have Susanoo without a MS eyes, so what do you mean by (he didn't use the Sharingan to seal him?) of course I didn't mean that he directly sealed him with his Sharingan, but he sealed him using one of his Mangekyo Sharingan techniques.
And as I said.. just because Madara didn't show any sealing tech's doesn't mean he don't have any, he fought against the best Shinobi with sealing Jutsu's, you think he simply didn't copy any of his sealing Jutsu's with his Sharingan? I'm not saying he did, but he might have copied some, who knows.. he might also learned few during his arsenal, Madara is not just any typical Shinobi, someone like Madara should have many Jutsu's up his sleeves.