There is only one area that saw a lot of fighting, and that is in the Krajina in Croatia. That's also the area between the Austro-Hungarian Empire and the Ottoman Empire. Serbs were actually recruited to that area as a bulwark against the Ottomans. But the Bulgars, Albanians and Serbs were firmly entrenched inside the Empire, and for hundreds of years, there was no fighting. The 19th century saw the first independence movements in the region, and there was a great deal of fighting then, but it was against the Ottoman Empire.
I would subscribe to your point of view for the 20th century, especially the first two decades.
Afterward, the Balkans were swept up in Axis-Ally intrigues with Albania, Bosnia, Croatia, Bulgaria, lining up with the Nazis and the Serbs and Greeks lining up with the Allies.
After the war, nothing happened until the 1990s.
As to the geostrategic importance of the region, it used to related solely to the Danube, and the fact that this river was key for trade. But now with oil and gas pipelines stretching from the Caspian to the Black Sea and the Adriatic, the region has become important for other reasons.
The fact that the place resonates with the population to this day shows that 700 year old animosities lie just below the surface. To hold a grudge for 700 years means that something is going on, even if the level of violence is suppressed by the rulers.
Yugoslavia was a "success" because Tito kept on lid on things, not because he fixed them. Once the top of the pressure cooker was removed, boom!
I remain puzzled. Policies not Politics ---- Daily Landscape
I would contest this idea of a pressure cooker being removed causing the mayhem. It was not that which caused it. It was the division of land/property without any regard for a fair division among all ethnic groups. That's what caused it.
Are you refering to the land grab for the Serb Trepca mine complex North of Mitrovica, which is estimated to be worth over $5 Trillion dollars with one of the largest coal reserves in Europe?
...for those who still use coal.
Other reasons: oil and gas pipelines from the Caspian into Europe.
Unless you have better maps, I must admit that I don't quite get it. Russian influence in SE Europe & the Adriatic seems more plausible to me as a cause for concern - even in the 90s, when Russia was in decay. Empires come & go & come & go.