If it reaches hurricane status, it could devastate the island of Hispaniola (Haiti & Dominican Republic)
On a more positive note, the Hispaniola mountains of Cordillera Central with Pico Duarte; Cordillera Septentrional, and Sierra de Neiba mountains are tropical storm killers. In other words, the rugged and high Hispaniola mountain ranges are awe inspiring tropical storm killers.
Worst case scenario for the rest of us is that Dean would skirt Hispaniola and Cuba mountains. We should shudder at the thought.