It promotes camping on the opposite end. And promotes rushing for whoever puts it on. It can be used defensively, but it usually isn't

To be fair, the best idea they had was limiting movement speed with it. No need to be sprinting with a shotgun. Messing with ammo never works. It's only made people choose the crutch weapons that can one hit instead. This is why you don't see a plethora of shotguns that are different. Because if it can't one hit, it's not needed. Any true shotgunner will tell you it doesn't need to 1 hit. Ammo effects the wrong trait. Make them slow as hell