In the Balkans, Greece has the edge if you exclude Turkey.
They have been over-spending too much in the last decade. That is why they are bankrupt at the moment. Greece won't be able to keep its current army assets for the next decades. In the coming decade I see Romania and Bosnia growing stronger.
Also, for argument sake, let's say a third Balkan war erupts. Would Greece be able to finance a war? Germany would cut their financing to Greece and they would collapse the next day. The Balkan countries can't wage war independently. The Balkans is where Turkish, European and Russian powers meet. I don't see war happening between Turkey and Europe.
Balkan war could happen if Russia starts supplying Serbia and Bulgarians to destabilize the region. Russia has serious potential to do this as retaliation against NATO expansion.
Strongest army in the Balkans is Turkey. They would definitely have a role in protecting Bosnia, Albania, and Macedon. These are friendly key countries in protecting Istanbul.