Hmmm. BLM has some decent native enmity spells actually. Many of the same that a tank would /drk for.
Stun: 180 CE/1280 VE
Aspir: 320 CE / 0 VE
Aspir II: 320 CE / 0 VE
Aspir III is probably the same as I and II, but I don't actually see the value listed anywhere.
And like any job, you can get additional spells/actions from subjob. /BLU would offer cocoon and a large array of extra enmity spells. /PLD for Sentinel and flash?
While BLM's selection of enmity gear pales in comparison to that of tank jobs, it's not like there isn't any. I see about ~+58 in gear possible without digging into augments and such if there are any. Although none of it is ilvl, so it might be advisable to not use any in those slots, focusing instead on recast reduction. This would cost 13 enmity+ dropping the total to +45.
Now, keeping hate via dealing dmg... well barring low enmity DD like RNG or SMN, you basically have to be doing more dmg than the DDs. And a lot more. Cause you're losing CE, and they aren't. Oh, and MB would be terrible for this as MB have drastically reduced enmity gain.
So BLM has some gear and tools for the job, but I have to agree with snaps about the CE loss.
BGwiki said:
Instead of functioning using the normal Enmity formula, Black Mages with Mana Wall active appear to lose a static 180 Cumulative Enmity per hit.
That is
Brutal.
For normal DMG, a player with 3k HP would lose 60 CE for taking 100 DMG. That's before enmity+ gear or other CE loss reductions. And you can reduces that loss by taking less DMG or adding more Max HP.
But 180 CE a hit is harsh. you lose the entire base CE component of a stun in a single hit... Against a fast hitting or multi hitting foe your CE could bottom out fast.
I be interested to see if enmity+ gear can reduce that CE loss though.