I like the current move, but Turn Undead is a good candidate for a custom move since it touches on your game's unique cosmology (like Last Breath does). So if it's not quite right for the undead/cleric relationship you have in your setting, tweak away. :)
Absolutely right, John. There's room for Turn Undead to be more controlling, exploding or less powerful as the case may be. The moves, in a lot of ways (especially the magical-type-moves) say things about the world. Especially the first condition of "in our cosmology, is this a case of 'to do it, do it' or not?"