First of all, you cant compare Orochimaru and Sasuke because Oro was very sick at the time and couldnt perform any of his jutsus that almost grants him immortality in battle(eg. Orochimaru-style substitution jutsu, shading his skin to heal injuries, conncecting his body after bisection, complete regenaration of his body...) and we dont need to talk what Oro is capable when in use of offensive jutsus(eg. thosuand snakes, striking shadow snake, edo tensei, Manda summon...) He was only capable to take his true form after many experiments and in that battle we saw his most vulnerable state which he uses only when the person is ready to give his body without any fight...
For the J-man, anyone can easly contradict your stupid statements:
1.) Thats stupid because Jiraya can use also double rasengan or giant rasengan in battle and pawn little chidori that cant increase his volume of use, while the rasengan can...
2.) When J-man enters sage mode its already a lost fight for Sasuke because he doesnt need to use giant rasengan or any other sage art jutsu...he just needs to use his genjutsu with Ma and Pa and the battle is over cause Sharingan cant counter in any way sound genjutsu(because sharingan is a visual genjutsu) and if the rinnegan cant do anything against that jutsu how can the sharingan counter it.
3.) Yeah, and so...
4.) Hahahaha are you stupid or what:"if jiraiya tries some crazy shit like to KILL HIM" wtf...its a fight, afcorse he want to KILL HIM!!!

and what will a poor summon like a bird help against Gamabunta...
5.)Jirayas moves in sage mode are very fast and even if the sharingan can figure out Jirayas moves, who knows if Sasukes body can keep up with it...we all know that in some fights like Kakashi against Zabuza, sharingan enabled to read Zabuzas moves but if the body cant react in time because of fast speed its meaningles...so its just enought that Jiraya uses kebari senbon and its over...
For the conclusion I just want to say that even Itachi on his full health with Kisame said that if they fight him that he doesnt know how much would it last and what would happend, and as we know Itachi can pawn Sasuke even when his sick so afcorse Jiraya can destroy Sasuke if Itachi with Kisame retreated. JIRAYA FOR THE WIN!!!!