Re: High kicking
If you want to see the effectiveness of high kicks, just search for some highlight reels of Mirko "Cro Cop" Filipovic. You can find many on You Tube. Mirko has knocked out more opponents with a kick to the head, than any other method, and we are talking about heavy weight mixed martial arts professionals. The caliber of opponents he has defeated with these kicks is just as impressive as the kicks themselves.
Of course this is one man, with an exceptional talent, but it should put to rest any controversy to the effectiveness of the strike. Like many previous posters have mentioned, it's all in how well you can deliver the strike. The problem for many people who train this type of strike, is that they train for Karate, Taekwondo tournaments where their goal is to reach the head, but no necessarily impact with power. The latter is a much different skill.