I have been meaning to try out Voracious Trunk on a few monsters/NMs but I keep forgetting.
i haven't found a instance where its really usefull, it doesn't replace a conventional dispel like blank gaze or geist wall due to the longer cooldown and i wasn't able to steal any effects worth stealing.
most of the time you end up with something like additional elemental effect on hit or spikes but mobs are usually strong vs the elements they cast or maybe some +att buff with short duation that competes with natures meditations slot.
stolen buffs also seem to have short durations, i think i read somewhere you get the duration left at the moment you stole them.
same for osmosis. its a shame, could have been a really unique spell.
don't think there is much reason to stack BLU skill besides occultation and even there comes the point where i'd rather favor fast cast over a extra shadow.