It was only a shot kill if you were skilled enough to get two consecutive headshots, AND you got the DoT effect. Unless you were getting team-shot with by people who were carrying multiple versions of the weapon, it was a very simple situtaion to manage. When you take the first shot...and notice the burn....you take cover immediately. Wait for the burn to wear off, and your'e health to recover. Then re-enter the fight. Plus fight the Thorn user---whenever possible---from cover. The two-shot-and-walk style was only a problem when someone so completely got the drop on you, that they would have been able to kill you with just about any other weapon in the game. Like I said, Thorn was simply annoying because it had the power to force you to have to fight it in a particular manner. Not that you couldn't effectively fight it. IIRC. The weapon witht he fastest TTK in the game was The Stranger's Rifle...and you never heard complaints about that weapon being OP.