From the videos I've seen of Cyclone Strike, I have a suspicion that the "pull" might have a larger range than the explosion. This leads me to wonder if the Implosion rune only increases the range of the pull (and not the explosion), which the wording actually seems to suggest.
I'm just gonna guess it has an 8-10yd explosion range depending on how tightly the mobs are pulled in to you. It doesn't really matter how big the explosion range is so long as it hits most of the enemies though for efficiency I can see why you would be interested in that. If the skill proves to have an explosion radius too small hit all or most of a large pack of mobs it pulls in it may still be worthwhile to combo with another pbaoe.
If the skill proves to have an explosion radius too small hit all or most of a large pack of mobs it pulls in it may still be worthwhile to combo with another pbaoe.
I think that's going to be true regardless of the AoE on Cyclone Strike's explosion. The damage on the blast is low compared to other pb-AoE skills, so after the first cast to pull in enemies you're better off using your spirit on more damaging spenders like Vulture Claw Kick (LTK) or Explosive Light (WoL) till all the enemies around you are dead. And that's a good thing, since it encourages skill switching.