Bad hand dropping habbit.

yeah, definitely

As long as I continue to break ribs and bruise limbs, yes, we’ll have to agree to disagree.

that’s really not true. The hook punch I learned in CMA and JMA was different from the one I learned in thai boxing. Not by much, but it was different nonetheless. The roundhouse is different also. Same general concept, but somewhat different mechanics. the teep and front kick differ somewhat also, as do other techniques.

A different perspective

Here’s an opinion from someone with a different perspective. I have “cross-trained” in not only Kung Fu but also in Tae Kwon Do and in several different Karate forms as well. From my experiences, Tae Kwon Do especially teaches specifically TO bring that hand down when throwing that rear leg roundhouse. It is the old adage of “for every action there is an equal and opposite reaction” thing- it is why Karateka use a “draw hand” when punching (forcefully pulling back one hand while punching with the other). It DOES add power to the kick, it DOES help facilitate the hips turning…and it DOES leave your chin wide open for a moment. This is one of the reasons we Shotokan guys tend to clean out a Tae Kwon Do guy at tournies. However, if that kick lands…it’s BAD news. Heck, even if you manage to block the kick, it still hurts.
In general, by dropping that hand when kicking, you are gaining momentum and power but leaving a hole in your guard at least momentarily. It’s a trade off. If you are realativly certain that the kick will land (like if the guy is worn down and his hands are held low to begin with) do it. If you are leading off your fight with this technique (and why would you to begin with) keep your guard up or you will BE that guy who is worn down…
Just my 2 cents…