I honestly think if Thorin had followed Roäc's initial advice the armed standoff would have been avoided. Having let the Lake-men know he was alive, he could have negotiated directly with Bard as their chosen representative, and continued detesting Thranduil from a soothing distance! (The question then becomes a combination of 'where is Dain when the goblins arrive?' and 'are Thranduil and Bard able to scramble quickly enough to respond when the goblins arrive and there aren't three battle-ready armies already conveniently in place to hold them back from directly assaulting the Mountain?')