Here's a Poynter column about the ethical issues surrounding the decision to show or not to show the coffins.
Photos of Soldiers' Coffins Increase Understanding Through Visual Storytelling
War is about heroism and about horror. War reflects battles won and lives lost. As citizens who send our military men and women into combat, we must comprehend the commitment, the courage and the cost. We must grasp what it means when our fighters fall. We must try to understand the pain that people endure when losing loved ones who wore uniforms -- our uniforms -- in warfare.