I think that destruction of the necklace was very pivotal to Naruto's development. To this point, it has been a crutch for him to bail him out should he lose control. And now that it is no longer there, we can see Naruto's will of fire. It's a common theme that even against the toughest odds, he wills his way on top. And I think this is yet another challenge for him. His friends, his village, his girl...he will look to them for strength in order to be able to control and suppress the Kyuubi.
When this battle is over he will be able to see the city laid to waste, not just by Pein but by him. He will take to lessons away from this. 1. He will need to become even stronger to protect the people he loves. 2. He needs to learn to control and suppress the Kyuubi's powers so that doesn't happen again. It would be great if he is able to meet Killer Bee and maybe learn tips from someone like him who has been able to co-exist with his Bijuu. I think the time is ticking to the day that the seal on the Kyuubi completely breaks, and when the time comes, Naruto needs to develop his own strength to contain, control, or destroy that power.
I am also wondering how badly damaged Naruto's body will be when he is brought back to human form. And I would like to see a final exchange with Hinata. Something along the lines of Sakura trying to heal her (even though she knows the wound is mortal), and Hinata telling Sakura it's a lost cause and pleading for her to go save Naruto.
No. The rods fell out when he went kyuubi. Right now 6 tails just wants to kill Pein.
It would be awesome to see Naruto and Killer Bee training together.
And I think the damage would be pretty bad. Considering how bad it was when he came back from 4 tails.