Moon Flute is a big old nope. It's a damage loss, doesn't make up for the lack of seven or so filler spells. Only time I can see Moon Flute being useful is when you know a phase shift is coming up with the boss being invincible for a while.

Red Mage highlighted the issues a bit more, I think. The damage numbers were closer, Red Mage ((In slightly inferior gear, due to me just letting my BLU keep on his swanky clothes)) hitting for 750ish a cast, Blue Mage hitting for 690ish a cast. And that's the issue, three is a .3 second difference in cast times for me ((1.98 Jolt 1 to 1.9 Blue filler)) but Blue Mage has a 20% increase in damage over the Red due to Maim and Mend and a 15 potency advantage over Jolt 1 with Off Guard on the target. Then again it might have to do with how scaling from Maim and Mend and Off guard work, both only adding to the base 130 while the 30% from Red Mage gets added to the 180. ...nope, even then it should be what, 260 from Maim and Mend and Off Guard doubling the potency of the filler to the 240 from Jolt 1 with Maim and Mend 3.

So...yeah. I think that more or less proves that Blue mage scaling is too low right now. So thank you, Phoenicia, for making me get off my backside and test something with potency and cast time closer to what the Blue Mage has. If the additional scaling from gear were really making up the difference for Blue Mages lack of a main weapon then Blue Mage 130 potency spells would be hitting for more then Jolt 1. Considering that fillers are hitting for 8% less I think its safe to say that Blue Mages are about fifteen or so percent behind from where they need to be in that department.

Now the question of whether or not fixing that divide would close the gap between BLU and other jobs is another story. I THINK it would close to gap to the point where we'd see the standard differences between classes and not a clear divide.