I think you're confusing the terms overpowered and unbeatable to mean the same things. They are not. A OP weapon can be counterable. You can be beat someone using a gun that is overpowered. All an overpowered gun is is a gun that gives someone a decisive advantage against other people who do not use that gun. To the point where it reduces the amount of skill needed to compete with said weapon or increases the level of skill needed to overcome it. For instance if you have two competitive players in a mutual situation and firefight it should be the players that decide the battle not which one has the better weapon. Now do all good weapons fall into the OP area no but if some do they should be relooked at. I do think Thorn falls into the realm of OP because it creates unfair advantages that have to be taken into account. Even then it may not be enough.