I'm not talking about healer DPS! Click me!

[FunkyBunch]

I vehemently disagree.
At low levels, you can pull off 2 or 3 Fire IIs max. If you are paired with an archer, they might also run out of TP. The mobs have such a large amount of HP that you're just better off killing a mob there and then. If you're swapping into ice mode, and the mobs are still at 77% HP, then it's just slower.

You can always pull off 4 Fire IIs minimum (before you get F3) unless you're terribly, terribly undergeared.
And it may not seem like you're killing them faster, but you are. There is no way it is ever faster to do F1.
You will always be able to cast AT MOST one more F1 than F2, no less, because F1 is 80% the cost of F2 at every level and because there's never a time you could cast 10 F2's.
180 potency vs 300 potency
180x5 is 25% less than 300x4
Even if you're only getting 3 F2's you're still doing 900 potency vs 720 potency with 4 F1s.

This doesn't count the fact that with F2 you have 3 times the crit opportunities per cast.

If the mobs are dying at different rates, it's because the players aren't properly rotating their targets which is not the AoE players fault. And the AoE player should switch to single target at 2 mobs. (unless they're a dragoon and then they should be DoomSpiking still anyway)