In case links frighten you, or you can not be bothered to read past the notes for other classes, or just get distracted every time you read about the revamped Onyxia raid we are getting (like me), I will helpfully re-post the Mage notes below. The buff from using 4story Luna stacks up to 4 times instead of 3, and each application increases mana cost by 130% instead of 200%.
The effect from triggering this talent now removes the mana cost of Arcane Missiles. In addition, the chance for Arcane Blast to trigger this talent is now 8/16/24/32/40%. All other listed spells continue to have a 4/8/12/16/20% chance to trigger it.
Arcane Blast is stackable up to 4 now, instead of 3. The damage increase per stack remains the same, at 15%. Only the mana cost has changed, and it has actually gone down. Instead of doubling with every stack, it has gone back to something closer to the pre-Wrath era 130%. This means that the mana cost per stack now looks like this.