Imitation, they say, is the sincerest form of flattery. More than a quarter of a century after Pernod Ricard signed its Havana Club joint venture with state-owned Cuba Ron Corp, Diageo has followed suit. The group’s Santiago de Cuba agreement, announced earlier this month, is one of the most eye-catching spirits deals of the year – but it shouldn’t distract us from the huge challenges facing the rum category, says Richard Woodard.