About Naruto's new training strategy, actually it should work pretty well. Yeah, it's a whole bunch of Naruto's training, look at this is way. Each Naruto has a certain probability (just about the same probability, since they're all Naruto) of succeeding at understanding something/accomplishing something during training in a certain time span. If you increase the number of Narutos training, the probability that one of them will achieve some measure of success in a given time frame, is increased.

Also, Kakashi explained why this method isn't for everyone. Not only can most people not create the same number of clones, most people can't sustain a shadow clone's existance for as long as Naruto can. Straight from the mouth of Kakashi. If you found a Jounin who could sustain, say, 3 clones for as long as Naruto can sustain 20, then yes, he could benifit from that training method in all likelihood. But as of right now, we don't that any ninja we've encountered can, and we don't know that any we've encountered can't, except kakashi, and probably sakura.

And if this is a cheezy way to make Naruto more powerful, I'm all for it. That fucking sharingan is second to none in cheese factor.