I've just got our 15 year old MMA student into doing kata and Bunkai....and he wants to grade TSD now. Why? because he's seen what we do and believes it will help make him a better fighter. You know, I do too. It's all in the enthuisasm and the presentation. Show them how it works, every technique should produce an ouch from the Uke. Make each of them Uke in turn. Nothing like a bit of realism for the light bulb to light up in their heads.