So before Patch 3.0.8, I always carried with me at all times, two stacks of [Arcane Powder] (40). I always throw down a table in BG’s or instances, and always buff with my Dalaran Brilliance. Yes I even overwrite an existing Mage’s Arcane Brilliance if it is already up. I like this icon better! I even have my Cryolysis3 mod auto restock my Arcane Powders back to 40 whenever I visit a Reagent vendor.
When I logged on, I noticed that my two stacks of 20 [Arcane Powder] was now one stack of 40. Oooh a free bag space! I went to the Reagent vendor to see how much they now stack to. [Shift] + [Left Click] the Arcane Powder and saw that it now goes up to 100! Not a big buff, but I do enjoy freeing up bag space!