I hope the binding seal is something that only Jiraiya knows how to make. What good would Naruto's ultimate Kyuubi chakra be if Akatsuki was just like, "whatever, faggot. Talk to the hand. I'm putting up the seal!" If I recall correctly, Kakashi is well-versed in seals himself so if he needed to get the seal from Jiraiya, it's encouraging that only Jiraiya -- not Kakashi, the master of 1,000 jutsus -- was able to provide the seal. Edit: But then again, Orochimaru is also well-versed in seals ... albeit curse seals, but that would just be worse.

Also, Naruto did learn how to delay, if not neutralize, genjutsu. I guess that can be counted as a new skill.