I know he didn't use the frog katas when pein initially launched against him because Naruto's goal was to grab the chakra receiver so he could stab himself with it and then find Nagato. I do agree though. Someone said something like "even if he gets to him what can he do in 4 seconds?" That chakra absorbing Pein was completely pwn3d in like half a second...and the way God Pein was kicked around on page 12 makes me think Naruto wouldn't have too much trouble casting kaownal on him.I wonder why he didnt use frog katas against him, sure did take out that absorbing pain in one shot, he could hit him, and just go and beat the crap out of him.
On a separate note, and I'm sure this has been discussed in the past as well...but given how similar the spelling is between Naruto and Nagato I have to feel like there is some significance in the differences. I don't know anything about Kanji but can anyone tell us about it? Is there a difference in the Ru and Ga in the middle of their names? I think it's obvious that, to some extent, they are meant to mirror each other slightly in that they both are Jiraya's students and are the two chosen ones (one to destroy the world and one to save it). It's hard to really know for sure because in translating to English, so much is lost.