While I havnt tried a P360... mechanically, its pretty easy to see that there are difference that will make them less responsive to a wico.
They both have a round motion... and that means that if you roll the character in a circular motion, it will be smooth and seamless.
However, if you were to go directly from left to right - there would be a gap to cross. The distance from left to right = the reaction time speed.
The wicos have a very fast reaction time, as there is litterally no gap. The switches are 1mm away from the actuator, and each switch is about 1mm from activation. You do not have to press the joystick to its fullest direction.
In a 360, the optics can be as good as a leaf - better since they do not get bent out of shape. However... I think it really depends on how far appart the sensors are from activation. Im willing to bet that they arnt as close to activation as the wicos. This may have to do with how accurate the sensor beam is. Also, it may have to do with safety - as many games you need more activation space (dead-zone) to avoid hitting the wrong directions on accident. (for compatibilty of other games)
The other factor is leverage. If the sticks pivot point is too low, it will take too much travel to get the actuator to ht the switches. And, the higher the stick, the more distance you hand has to move
thus again, making slower reactions.
Also said, the springs vs gromet plays a factor here too.