I'll speculate here on why Naruto has the same form when he draws on kyuubi chakra now that he had when he summoned the fox's power while in sage mode. During that chakra tug of war, Naruto was infused with nature energy, so it's conceivable that the kyubi chakra that Naruto extracted during the tug of war mixed with the nature energy within him, and the seal locked away that mixture of chakra instead of just the fox's. If this is true, I'd bet there's a limit to how many times, or how much demon chakra Naruto can draw upon and still take on that form, because I don't think he had as much natural energy in him as the demon had chakra to tug away.

edit: This might actually make a pretty decent way to gather sage energy. Before battle, infuse the demon chakra with nature energy. Then all he has to do is access the demon chakra. This is way less awkward than the method he developed before, and it's also more powerful.
Quote Originally Posted by darkshadow View Post
It isn't more broken at all, in fact it's weaker. Minato can teleport wherever the seal is, he doesn't have to direct himself to someplace. He also knows when the seal is in motion, which is how he saved Kakashi. Minato's version is just so much more versatile.
What do you mean by "direct himself to someplace"? I might agree (though it'd be arguable) that teleportation using the seal is more versatile if it existed as a technique in a vacuum, but Naruto has a couple of other powers such as sensing both chakra and negative emotions. With those abilities, Naruto's better off with a teleportation technique that doesn't require a seal.

Plus, using Minato's teleportation in combat, on the fly, requires throwing a seal to the intended destination, or some kind of deceptive/hidden tactic to place the seal for use at a later point in the fight. Considering that a projectile can be deflected, and that there's both mental and overhead of execution for deceptive/hidden tactics, use of the technique can be made to lack spontaneity. No setup required teleportation = more spontaneous teleportation.