Basically, from the abyssea trigger system we learned that a monster readying a WS is a specific state of the monster.
I propose a Job trait for monk based on that specific state.
Name: make one up i don't care
effect: When a monster is in the state of "readying a tactical point special attack" if a monk delivers a successful WS, the monster is struck with an inhibit TP effect. This inhibit tp effect could be set up a number of ways, but if possible i feel this would be the best way. Unlike other effects that inhibit tp like chi blast, and Yurin:ichi, this effect would cause the monster to choose to WS at a higher % in effect changing its AI temporarily. It could be "won't ws til 200% tp is reached" and then gear bonuses could then raise the %.
In essence, the ability is based loosely on the psychological aspect of martial arts. When an opponent attacks strongly and receives immediate pain, he is less likely to ambitiously attack with a strong attack again until he has a chance to regain his confidence. It is also a concept used in training dogs =) go go spray bottle.