IMO there's a higher probability of Herceg-Bosna coming to realization than a country called Herzegovina. In fact, Serbs from Bosnia would be more than happy to support the independence of a Croatian-led Herceg-Bosna. Perhaps not because of "close, brotherly" ties, but because it would trigger further disintegration of the so called country of Bosnia and Herzegovina and eventually manage to gain independence in Republic of Srpska as well.