A cancellable event for when a player's getAttackCooldown() resets to 0.0 would very useful.

Example use:
@EventHandler
public void onAttackCooldown(PlayerAttackCooldownEvent event) {
Player player = event.getPlayer();
if (event.getCause() == PlayerAttackCooldownEvent.Cause.SWITCH_MATERIAL || player.isOp())

}