What makes Korean touch typists really fast is the semi-regular symbol construction. Unlike an English keyboard (whether Dvorak or Qwerty), the Hanja consonants

What makes Korean touch typists really fast is the semi-regular symbol construction. Unlike an English keyboard (whether Dvorak or Qwerty), the Hanja consonants are primarily on the left while the vowels are on the right. So you typically have an alternating typing rhythm which can make typing extremely fast. Dvorak, to a similar extent, seems to be closest to mimicking this style of typing (although I hear Colemak is better with the keystroke distribution).