In OTL Serbia and Russia howled in protest at the Austro-Hungarian annexation of Bosnia-Hercegovina in 1908 [and Italy muttered in protest?]. The Serbs did a mobilization and the Austrians and Germans told them to de-mob, "or else". Whereupon the Serbs stood down.
If Germany did not throw its diplomatic weight fully behind Austria-Hungary, how might the situation have evolved differently, if at all.
I'm not sure what the Serbs were demanding, either parts of Bosnia, or Ottoman territory to the south "in compensation". It seems to me that absent big power support up to and including mobilization, Austria-Hungary would never concede any directly occupied territory to Serbia, and Serbia could lift territory off the Ottomans only through war...and war in 1908 might not have gone as we'll for them as the Balkan wars.
Austro-German solidarity inflamed Russian nationalism and Pan-Slavic settlement. The Russians felt scored against. However, in the circumstances of 1908, with a lost war and an attempted revolution in recent memory, Russia backed down and advised Serbia to do the same, ending the crisis for the moment.
If Germany had *not* taken such an unequivocal stand, might saber ratting between the Austro-Hungarians on the one hand and the Russians and Serbs on the other, have kept going and escalated into a conflict too big to be contained, resulting in an early WWI?
In this instance at least, would we be wrong to think the Germans of 1908, with their "peace through strength" policy actually won "peace in their time"?