im of the opinion that to strike vunerable areas is clearly a good idea for effect, it's seen in combat sports and real life violence often. (a good clean shot always works)
however the skill is in the application against someone who is pumped up and in your face/attacking,
this is where many of the modern, expensive commercial groups fall down, kid themselves that their lethal and also kid the students, but its magic you see...........
and groups like Rauls, who practise Bogu really have the advantage, the application becomes live and requires experience and resilience to have effect. (often not in the boju gear, thats not the sole point, its tool development).
Any good Okinawan karate is full of Kyusho and Tuite (the older family systems more so),
granted Oyata Sensei really was and is the man in the public eye, but it is in all the systems via the classical kata, just gotta find it and work it.
I really struggle with many of the other organised PP groups to be honest, far to much science, bull and sales
not enough good, basic Karate training.
Another element is 'tool devleopment' delivered by traditional conditioning, done heavily it makes a REAL difference to strikes effect,
but that is a little hardcore for most including me, I work steady with this element.