When WP impellers break apart, they can send plastic bits into the narrow water passages in the head where they block water flow and can cause cracked heads from localised overheating.
So I was thinking, what about a WP gasket that is essentially a mesh screen which covers the outflow section of the water pump? The, if the impeller breaks, the bits stay in the water pump and can't circulate through the motor? Sure, the bits will chew up the impeller more quickly, but at least you prevent plastic bits going into the motor.
Should I start working on the patent?