Sosai speaks on Chokusetsu Dageki
:
http://www.kyokushinmail.com/koya/letters/letter5.htm
I'd like to see Kyokushin tournaments that allow palm strikes to the head and punches to the body. The art really amazes me simply because the practitioners still adhere to a lot of old-school budo principles and traditions: meditation, forms, breaking, doing crazy stuff under waterfalls and in the snow.
To be fair though, Kyokushin directly takes the low and mid roundhouses from Muay Thai - I don't think the art would last in the ring at all if not for this, hardcore training or not. The knees also look very similar, I'm curious as to how they're trained and how different they are from MT knees.
Also to be fair, Kyokushin karatekas train harder than the Thais only because they don't fight nearly as often. When you're fighting every two weeks since a very early age in full MT rules, you can't afford to do crazy stuff in training and hurt your body. Personally, I think that the fighting a opponent who's trying to knock you out every two weeks since your teenage years is much better "training" than any amount of sparring without protection.
Kyokushin is still a very cool art though, I love watching people split stones with their chops. The kata are also very nice.