I'm aware of its general history, from Ottoman to Yugoslav rule and now independence, but what event(s) led Croatia to dominate shoreline of the Adriatic Sea relative to Bosnia?
It wasnt Croatia's influence as much as it was conflict between Ottomans and Venetians acompanied by Ragusan rivalry. Ragusa was a small mercantile republic, and a tributary of Ottomans, who feared Ragusa. Under their influence Ottomans demanded thin strips of lands to separate Ragusa from Venice on both sides, nameli Neum on the North and Sutorina to the south. Bosnia kept possesion of both those exits to the sea until 1947 when Sutorina was given to Montenegro.