I'm sorry, but I really don't get it. There are some many standart way of killing people with weapons or strikes that why base you special move, you signature attack on something that's, well... perhaps only slightly faster or stronger than a usual attack?
Sure, there are some nice examples out there (The Ama Kakeru Ryuu No Hirameki or Kuzu Ryuu Sen from Ruroini Kenshin, Jyuken attacks from Naruto, and yes, Falcon punch.) but most are just seen so many times with so little variation.
As i said earlier, my personal selection would be a kind of grand karma imbalance: Enemy becomes the target of increasingly deadly accidents while his every action helps your plans along. You give him hella lot negative karma and yourself a lot of positive karma. It's indirect, the enemy might not even realize your responsible before dying a horribly accidental death and a curse as a signature move is not often seen.
I don't mean to hijack the thread, but could someone please explain to me why most seem to prefer a directly damaging attack or just purely physical moves? Why do people like them so much?