Seriously.

The introduction of more Jinchuuriki would be phenomenal. Although, as Terra mentioned, it'd be a real bore if we were introduced to a good number of the remaining containers, and all of their backgrounds shared all the drama and self-loathing and loneliness as Gaara and Naruto were familiar with.

From reading over the information on the Legendary Bijyuu, I hope we get to see the container of Houkou (Gobi - Five Tails). He is said to be the third strongest of the demons, as it weilds power over all the elements. He'd be a badass shinobi, whoever's got him.

In addition, which two (three?) demons do you think Akatsuki already has? It's obvious they've extracted and store Shukaku (One Tail), but does anyone have any speculation as to who the others they've acquired could be?

Also, as Xan' had said, I do not think Kishimoto's following this exactly. He's simply drawing his ideas and inspiration for certain aspects from the legend of these nine beasts. i.e. - ( a ) Samehada being able to absorb chakra and store it, which may possibly feed Kisame, which would explain him possessing the largest storage capacity for chakra. I don't think he's got a demon within him, but in correlation to the Legend, the information for Isonade (Three Tails) was contorted and made to fit the Naruto story and that's Kisame. ( b ) Orochimaru follows the story of the Eight Tails, as it's awaiting a genius to restore his power or finding the new body that will grant him more power. Rather than Yamata no Orochi and the Yagami heir, it is Orochimaru and Sasuke. Sasuke's body and "awakened vision" will bring about a newfound power to Orochimaru that may be enough for his twisted goals.

On a final note (maybe), I want to see old Jinchuuriki. Kyuubi was too great to be contained, and allegedly used to cause all kinds of chaos everywhere, running rampant, doing what demon foxes do, until Yondaime showed up on the scene. We also know that in Chiyo's lifetime there were two containers for Shukaku before Gaara, as she had done the extraction / bonding technique for it, or something to that effect. Well, that means, while Kyuubi was free and frolicking about and then finally getting sealed in Naruto, Shukaku had been in three vessels already. The other containers I would expect to be older, and much more experienced than Naruto with their control / suppression.

Nekomata, Houkou and Raijuu sound too damn coo'. We need to see more Jinchuuriki .. Now!