I think your overestimating what the 4th did in Naruto's head. I seemed to me that he just closed the seal to end that rampage, he didn't recast the seal like he did originally. It's in the same state now that it was before he lost control fighting Pain.
The simple fact is, Sage Mode chakra wasn't enough to beat Pain on it's own, it's probably not going to be enough to beat Madara, or Sasuke by the time Naruto fights him again. And when Naruto has to access the Kyuubi's power again, the seal will break down again unless he does something about it in the meantime.
The only way I can see Naruto losing the Ninetails is if this course of events happens:
Madara collects all nine beasts. Naruto somehow survives the extraction. Madara awakens the Tentails. Madara is defeated before he can Seal the Tentails. Naruto seals the Tentails inside himself to stop it.
Well that's what I mean by training. That Killer Bee would teach him how to communicate with the Kyuubi and they could maybe create a similar relationship.
You seem to be implying that Bee gets along with Eighttails because Eighttails is a cool guy while Kyuubi is a dickhole. I was under the impression that all the Tailed Beasts were dickholes originally. Eighttails is only cool now because Bee has taken the time to forge a relationship with it.