There is nothing yet to convince me that the seal is breaking. Its still intact both on Naruto's body and in that dimension where he talks to the Kyuubi. There has also never been any evidence that any seal would just break over time. When Oro sealed Naruto for example he said the only way Naruto would be able to use the Kyuubi is if the seal is removed and it was. If any seal was going to break you would think one as simple as that would have been easily broken. Another thing is that seals are supposed to be permanent, like the sealing statue Akatsuki uses I don't consider that to be as powerful as the one the fourth used and that contains multiple beasts but nothing suggests that its breaking. So don't see the seal breaking without some outside interference.

I think whats happening here is this, the seal in Naruto is intact but the seal allows Naruto to gain access to the Kyuubi and Naruto is simply using more and more of the Kyuubi's power. Look at the seal Kakashi put on Sasuke's curse seal for example, that seal was working fine whether it was effective or not completely depended on if Sasuke wanted it to be.

Its just hard for me to believe that the fourth gave his life and used his most powerful attack to create a seal that would break in a fews years. I mean it did use a shinigami and if the seal on Naruto is breaking then the first four hokages will be released eventually then because they were sealed using the same technique and Sarutobi said it was for eternity. I mean why would the fourth give his life to seal the Kyuubi if it only meant that the Kyuubi would be released a few years later.

So because of the reasons I stated above I really don't think the seal is breaking. Naruto has access to the Kyuubi and he has control over the seal and just how much chakra is released. Why else would the Kyuubi be asking Naruto to remove the seal, if it was indeed breaking there would be no need for him to do that.

However if the seal was under Naruto's control then Naruto would be able to dictate just how much chakra is released and whether or not the Kyuubi is released just like Gaara was able to control if Shukaku is released or not. To transform to the state he is in, they showed us that Naruto actually traveled behind the seal to where the Kyuubi is.