Re: has anyone noticed yet?
ok one last thing to point out hopefully. regardless what you do with chakra whether its releasing it, shaping it, or changing it, it's chakra control. as far as I understand it handsigns give a medium for channeling the chakra into what ever form it needs so user for the most part only has to channel the chakra into the jutsu. wile the rasengan and fuuton rasengan don't require handsigns to do any of this its on the user to do it all. as for sakura being able to use nature manipulation i'm sure she probably could if she trained at it but as far as we know she doesn't use them yet. not to mention she was train by tsunade who as far as i know doesn't use the elements.
don't get me wrong im not saying that naruto could or didn't do the fuuton rasengan with one hand. all i'm saying is that he would now have a great amount chakra control possibly among the highest in the village to pull it off. but to me it seems like you guys think shape manipulation and nature manipulation just happen magically but in fact it using it straight up require chakra control because all it is is chakra. the reason it takes so long to get is because for the most part all the chakra control ninjas usually use is releasing just the right amount of chakra as well as possibly one or two other small things. trying to learn to do it all by oneself is probably pretty difficult which is probably why it takes so long to do.