Otto von Bismarck is famous for declaring in his later years that the next great war would be cased by "Some damn (foolish) [depending on source] thing in the Balkans".
Was this really so insightful, though? If a great leader declared a decade ago that "Bad stuff is going to go down In the Middle East" or "Watch out for Russia, yo", he'd be just as right as Bismarck, but for his contemporaries, it almost went without saying anyway.
Were Bismarck's predictions uncommon at the time? Or was it already taken for granted that the Balkans were an unstable political nightmare?
I don't know about his sentiments being unique but let's just say that it is highly unlikely that they were.
I mean the Greek Revolution, the Crimean War and the Russo-Turkish War were all fought within Bismarck's lifetime. Not to mention the many states jumping out of the former Ottoman Empire (Romania, Bulgaria, Montenegro and Serbia and Greece) all of them with irredentist mentalities and (in hindsight) very optimistic ambitions all did their to make the balkans known as "The Powder Keg of Europe" (the Megali Idea behind Greece for one and the pan-slavic ambitions of the slavic states for another)
So what am I trying to say? I can't give you any examples of people predicting that World War I will be 'caused by some idiot from the balkans BUT I can assure you that very few people would have been suprised if you went back in time and told them that the Great War started in the balkans.
I recommend History of the Balkans, Vol. 1 by Barbara Jelavich if you wanna find out more about all the reasons the balkans became the place they are and how many conflicting intrests there have been since the start - I'm warning you, the answer is a lot.