What do you want to talk about here? Karate as a battlefield art, kyusho-jitsu, or kata bunkai? You're sort of all over the place. As for karate as a battlefield art, karate was invented in the 1930s, when gunpowder warfare had already made all close-combat martial arts a very poor second choice for the battlefield- when this had been the case for centuries, in fact. It has no history as a battlefield combat art, except as an almost incidental backup to a soldier's rifle, pistol, and combat knife. It is a civilian art of self-improvement and self-defense, and has been for the entirety of its history. As for Kyusho, it has failed to live up to the claims of its most prominent practitioners whenever put to serious skeptical examination. At best it serves as an interesting supplement to a far broader training program: at worst it serves as a pernicious distraction from kata, kihon, and kumite. As for bunkai, they are all right as far as they go- but the line between discovering applications of a kata and inventing them is a very fine one, often too fine for me. If you wish to apply a kata, make sure that the applications that you're practicing are immediately and obviously apparent in its movements when even a modicum of observation is applied: otherwise, be honest about what you're doing and create combinations or sequences of prepared responses from scratch.