Huh, you know what? I'm hoping that the reason Naruto doesn't want anyone to see his training, is because he's experimenting with the kyuubi chakra. While thinking about why he would need to hide this training from everyone, this is the only thing that made sense, considering the big deal that was made about not using the demon energy. If this was the case, it would actually show that Naruto's done some maturing. Everyone's telling him "no, don't use this, it's no good for you, it's dangerous, it weakens you," but he's going "...uh...that might be kind of true, but ignoring this huge power source in me is kind of extremely stupid."

That's not to say he should or shouldn't be training kyuubi just to become reliant on it once again, but he ought to, at the very least, gain some new level of control, and a new technique with it, in conjunction with his sage techniques. Most of you are probably thinking about how cheesy it would be, but the stupidity of not doing this exceeds the cheese.

Hrrrrm...I think I have an idea for a line in my signature.