The issues with Toxicon become non-existent the moment they make it oGCD. I believe the idea behind it is to return the GCD used on a heal much like Afflatus. The problem with that is lilies are gained passively, while Addersting charges costs GCDs to obtain, so it isn't returning anything, and can even be the less optimal GCD to spend. If Addersting charges were gained passively, or from abilities like Haima, then using GCDs on the skill makes more sense. It is going to have to be adjusted, and can be taken care of multiple ways depending on how they would like the skill to be rewarded and used. It's more of a burden than reward right now, which is a shame as it is a fun skill.