Some random musings:
It seems to me that supporting the creation a single chapter for these independent countries and cultures, solely on the basis of them having once been part of a single state, might be considered offensive to the people involved. No one is proposing that Austria and Hungary merge their potential chapters, nor is anyone suggesting that the UK, Canada, and Australia set up a single chapter, though the cultural differences there may be even less distinct and they still share a single crown, language, etc.
If Yugoslavia was a fiction that the constituent peoples rejected, let's respect that, rather than suggesting that they "join together" again, for the purposes of Wikimedia. I am sure that differing legal and tax requirements in each country would support such a distinction. As for bringing the peoples of different countries involved in Wikimedia together, that would be the role of the Foundation umbrella. Right now, I think the Chapters Committee is doing an excellent job at that.
Danny