That's a pretty good question.
As far as peace goes, I think you hit it on the head, but my views differ from your when it comes to how the world could be destroyed.
You could interpret ''Destroying the world'' in a literal sense i.e Naruto becoming so powerful that he can literally destroy the world single handedly.
Or, you can interpret it like Naruto will make a choice that will ultimately effect the entire ninja world in a very negative way i.e he [somehow] causes another Great Ninja War with the entire world, in other words, the World War I of the Naruto world.
There's a number of different ways you can interpret it, but I personally think Naruto will either start a Great Ninja War, or awaken the Kyubbi and cause mass destruction throughout the nation.