I always thought the reason Naruto learned the types of jutsu he did was he sucked at controling his chakra...and altering it's nature sounds like the most complicated form of chakra manipulation. Other examples probably inculde The First creating trees from chakra, the second creating water from chakra, and the Third creating fire from chakra. However an elemental Rasengan would probable be quite boring, so hopefully Naruto will somehow learn a much more useful way to alter his chakra then just making it elemental.

And screw you Kishi for the gay "Not to draw this out..." --Cut away till next chapter shit, that wasn't funny, just irritating!