Deployment is certainly important and can most certainly lose you the game.
But I also know that dice can as well. I lost 2 games at Sullust due to improbably bad dice rolls. One game 6 black dice rolling back to back blanks at one target with no shields and 1 hull left, and the same thing happened with 4 blacks at another ship. Both were my opponents respective command ships, both would have won me the game if destroyed but left the points in my opponents favor alive.