Assuming that beheading dead Taliban was authorized (just exploring an idea here), what good would come out of it?

What would the psychological (if any) impact be on the Taliban? Would they be less hesitant to fight, or more aggressive? I suspect the war would simply get more brutal. While there are exceptions, compared to the Vietnamese, Nazis, North Koreans, or Japanese the Taliban have been relatively gentle with their prisoners (beheading is a form of execution, nothing more, nothing less). I wouldn't want to be a POW period, but if I had a choice of being detained by the Japanese in WWII or the Taliban, I would take the Taliban without a second thought.

My point is that our rules for fighting this conflict are about right. Sending the service member home that committed the beheading is probably appropriate (hopefully no more will come of it). If I recall President Bush literally wanted UBL's head (if you believe what you read).

On the other hand, I don't think we need to over react to this event. Simply say we don't do this, and be done with it. We sure as heck don't need to bend over to kiss the enemy's ass and apologize for offending them. Give it a break.