We south slavs never had much luck. Our area was always place of wars. Balkan was always important strategic place in all major civil wars of Roman Empire. Later in time foregin invaders needed balkan yet again in order to invade Eastern or Westrn Empire. Medieval age was full of treacherous wars between Austria, Hungary, Byzantine empire and Ottoman Turkey etc.

Wouldn't say that it is of some important strategic value. One has to consider the field of influence:

    [li]Croatia and Slovenia were for 1000 years Austrian and/or Hungarian, so their allegiance even unwillingly was always to the 'germanic west' since they were only caressed by them, as well as their culture was largely influenced by the Austro-Hungarian one.[/li]

    [li]The Slavic muslims (

Bosniaks) emerged with the rise of the Ottoman rule in the Balkans, they were so to say invented by the Turks and helped to thrive to what tradition and culture they today cultivate under the Ottoman Turkish gentle hand. So it is logical that their allegiance is towards Turkey rather than towards anyone else.[/li]

    [li]Serbs were occupied by both Hungary as well as the Ottomans. The medieval core of the Serbian nation did however managed to sustain themselves, mostly through the Orthodox church which nourished the language, culture and tradition of the Serbs. The only ally Serbs had were Russians, which were far away to bring any on-ground support but were tied to the Slavs of the south-eastern peninsula by tradition (

same kin, same religion). The allegiance Serbs have is towards the Slavic east, since together with Bulgaria they once formed it's medieval core.[/li]

As you noticed you have three factors on the ground; the west (Slovenia, Croatia), the south (Bosniaks), the east (Serbs).

With the fall of the Ottoman Empire the Bosniaks were left without any support, being percieved as 'foreign body' by all other Balkan nations. Slovenia and Croatia still enjoyed full scale support of their 'once masters' because of the proximity. Serbs managed to rebuild themselves as a kingdom mostly because of the mere population in comparison to others.