AF1+1 vs. DH+1 is a question of inventory management, not stat considerations.
Honestly, it's a very small difference. You would use DM+1 over AF1+1 because of 1 INT, which is max 5 damage. You would use AF1+1 for - enmity, which if you can tell the difference by eye balling it you're a whole lot better than me, and MP, which only plays an important role if you're nuking at max MP (very rare). Of these 2 reasonings, you could really go either way.
The issue here is inventory slots. It doesn't matter which of these 2 you use on nukes... it's pretty much going to result in the same thing. The reason I would use AF1+1 over DM+1 is because it has HMP+1, so it works as the headpiece for both nuking (non ES set), and HMP set. Because you got 1 slot doubling for 2 uses, it trumps DM1+1, which is 1 slot for 1 use. With the slot you save using AF1+1, you can add something else like a Swift Belt for /recast on your stun and stuff like that.
The exception is if you have Goliard Chapeau, which is HMP+2, in which case, the HMP+1 from AF1+1 is pretty much useless. In this game, it's really back to the original argument. I'd personally pick DM1+1 in that hypothetical situation, but since I don't have Goliard hat, I don't really worry about it. Seriously, if you're going to base someone's BLM on their choice of nuking hat, which it's not that big a deal to begin with, you are nit-picking...
Also, sidenote on one of the arguments. Whoever said max MP matters is probably a soloist. Max MP matters a ton when you are low manning and especially in hard solos, but it's not quite so important in team events. Unlike RDM, which is more based on MP regen in solo, BLM's total damage output is based almost solely on a combination of damage per MP ratio and max MP. Having a higher MP pool is the only way to raise your total theoretical damage output from 1 sitting beyond getting better gear. This is why you'll see or hear almost all BLMs doing harder solos are Taru.
