Odd that the Brits would worry about polishing off Yamamoto. They were keen to do away with Rommel. "Political" considerations didn't stop them from trying that. Likewise the Germans made an effort to kill high Allied commanders towards the end of the war in Europe, but I don't think they had any success. There is no point in mentioning specifics of the brutality of the Japanese before and during the war. It's not popular. War should be all about causing harm to your enemy. Eliminating high officers should be nothing more than a cost vs. effect calculation. Likewise with the politicians who start the wars, IMO.