Oddjob's hat was incredibly effective as a weapon is his hands, but it's not for everyone.
First of all, it requires a Randy Johnson-like arm to get it up to adequate slicing speed. Second, it requires a Greg Maddux level of control to get that accuracy. This is a boomarang situation; this is like throwing an enormous curveball. Finally, the lack of formal hats is a problem, and a top hat does not go with your going-out shirt, dude. But this doesn't mean hat warfare is dead. In fact, it's being furiously defended by the FAB Defense Gotcha Cap.