He helped Naruto increase his Taijutsu and combined it with shadow clone jutsu to maneuver his physical art in the air. He also helped Naruto increase his stamina more so he can handle more demon form chakra all the way up to 3 tails and help him learn Kai release weaker forms of genjutsu. That's it.
Rasengan was pre shippuden that allowed him to change in shape into the highest degree.
He really didn't teach Naruto much like changing Nature would be nice.
Naruto was actually even weaker imo after the time skip than he was before the time skip. Jiraiya failed miserably.
Jiraiya also screwed up Naruto's chakra control (both base chakra control and jinchuuriki state chakra control) by fiddling with the seal and trying to loosen it. The scroll toad even said as much and reprimanded him about it.
You say Naruto could handle more demon chakra but that's false, he couldn't even use it like he did vs at the valley of the end coz Jiraiya messed up the seal. Every time he used it now the kyubi would just begin to take over and he would lose control and fight like a mindless beast.
The things he did in the shippudden bell test were no different from what he was doing pre-time skip. He didn't improve at all in those three years. The only thing he did was get bigger.
He say he got more stamina and strength? Duh? He grew up. That would have happened anyway whether he was with Jiraiya or not, defaq you on about.
Manuevering in the air with clones? Defaq? Jiraiya didn't teach him that, he did that on his own.
Jiraiya trained him well BEFORE the three year trip. I can't deny that. He taught him rasengan, he taught him the water walking chakra control technique, and he taught him the summoning technique, all in a relatively short space of time.
But after that he did nothing for Naruto, in fact, he made him far less reliable as a teammate with that shit he did with the seal. Everybody had to always worry about Naruto losing control and he even hurt his own teammates because of it.
Everybody got better except for Naruto.
