The Ultimate Black Mage Resources with Damage Calculator

[Kenji1134]

Hmm, IIRC, to do the double Flare trick, much like the double F3 trick, one is affected by UI3 and one by AF3.
Under UI, Flare has 260*.7 = 182 potency. Under AF3, Fire 2 has 180 potency, but generally has a lower cost.

In effect from a full-ish mana bar, you can do 3 F2s and a Flare, which puts you at 0 mana and you need to transpose. This is a total of 1008 potency for your mana bar, and transpose is always up after Flare.
Going from UI3 into Flare for 182 potency, then a 2nd flare to 468 potency is a total of 650 potency, but even without doing any math, my gut feeling is that transpose wont be up in time.
Transpose takes ~5 gcd's to refresh.
So trans - tick (1) - B3 (1.4) - Flare (1) - Flare (1) = 4.4 gcd's. So transpose would not be up.
Also 468/4.4 = 106 pot/gcd, barely above B2 spam, and below the 3 F2 - Flare rotation.

Hmm, Ill get back to this idea later.

Edit: Returning to the idea.

I got ACT running for FFXIV this week... makes quicker testing a whole lot easier.

Baseline B2 spam: 98 dps on 1 dummy... 98 dps aoe... All tests are done on a lvl 1 dummy in the Bannock, that doesnt clip the other one with 5m range aoes... so its all effectively ST and AoE's that just hit 1 target.
Ranged Double Flare: *0 mana - Transpose - tick - B3 - *wait for tick, hit Flare a bit before the blue bar fills up - Flare - *back at 0 mana = 125 dps on 1 dummy, 91.25 aoe.
Melee Double Flare: *0 mana - Transpose - tick - B2 - B2 - *wait for tick, hit Flare a bit before the blue bar fills up - Flare - *back at 0 mana = 120 dps on 1 dummy, 120 aoe.
Ranged F2-Flare: B3 - F3 - F2x3 - Flare - Transpose - tick - *back to B3 = 151 dps on 1 dummy, 110 aoe.
Melee F2-Flare: B2 - B2 - F3 - F2x3 - Flare - Transpose - tick - *back to B2's = 132 dps on 1 dummy, 115.4 aoe.

Comparisons

If you can be in melee range:
Melee Double Flare is best, if you watch your mana bar like a hawk. If you get the timing wrong, then you lose the AF3 Flare and that just sucks.
2nd best is the ol melee version of the 3F2-Flare rotation, trading B3 for 2 B2's in melee range. ~96% as effective as the "New King" Melee Double Flare... but SOOO much easier to do.
And 3rd place in the melee category goes to the the old standby "mash Blizzard 2 until everything dies"... coming in at 82% of #1's dps... Also mindlessly easy and you never miss cause your target died...

From a distance:
Your best bet is the standard 3F2-Flare rotation using B3.
The ranged Double Flare rotation sadly falls flat in this category, coming in at 83% of the above rotation's dps, and for more work.

Conclusion

If you get the timing down, and can safely stay in melee range, this "new" Double-Flare rotation does seem to be our best option for AoE.
That said, the non-double Flare melee rotation is a close second, and likely easier to use in the long run.

And one last comment. Since I separated the damage into "total" and "aoe", I could do a quick analysis on the break-even point between [AoE * N] vs [ST + AoE * (N-1)]... and simply put, the magic number seems to be 4. On 4 mobs, a purely or predominantly aoe rotation is better than a slightly less aoe rotation...
So... the answer is 4... when you must choose whether to AoE... or AAAAYEEEOOOOHHHWWWWWWHHEEEEEEEE!!!!!