The hardest part about getting akaso isn't the drop rate....it's the 5 mules that the player has camping at the harvesting points and telling you to f*ck off.
I figure I would give an update on my findings on harvesting this in Yorcia Weald. Yes it is extremely rare, but you do not need "critical slice" to actually get it. Most of the time when that ability kicked in I actually got nothing sadly. Of the two times I actually was able to get it, neither were critical. Also, I managed to find one in a Soul Pyre. ^^ Hope this helps! GL hunting!
Yugiwo, my experience mirrors yours. Overall, "Critical Slice" has been the worst and most frustrating investment of Bayld I've ever made. I swear to baby carrots if I see another "Critical harvest! However, you were unable to find anything" message I'm going to strangle a cat.