You lose me at 2/3 of the voters agreed with whatever is put forward from the hypothetical convention. This seems like a great way to get popular changes (that might be unpopular to the current state legislature) approved. 2/3's is too high a hurdle for something too terrible to pass. The logic of "let's not risk it" could be used just as well to justify disbanding the NH state government else some extremists push through a terrible law.