Right after the ranger adjustment in an interview with SE, SE said that they were considering nerfing the damage output of BLMs. How they would do that and when (if they ever do) remains to be seen.
From an article with 1up awhile back:
1UP: Are you looking to do something similar with Black Mages? A recent trend has been these "Manaburning" parties where five Black Mages (and a tank to hold hate) all cast Blizzaga 3 and kick (arguably) too much ass, too fast. Black Mages can hit level 75 in no time using this strategy.
HT: The Black Mages have been way too strong and ever since we released the game, and we've been trying to make them weaker. But as you know, players always find creative ways to get around this (laughs). But as for what we're going to do in the future, we're planning to continue to look to those Black Mages and continue to adjust them.
I really hope SE does not *NERF* black mages. I have not played black mage as Sheala, but I watched Chaoskitten as a black mage in my static. The damage out put was fantastic, but everyone in the party broke into a sweat each time Chaos pulled hate off our tank, Taz. The shear nuking power of the black mage is set off already by her or his paper thin defence.
In addition, black mages (like other mages) have to contended with mana conservation, rising spell scroll costs, and a very low ability to solo. I will try to find the thread which states that killing monsters with spells lowers the drop rate. If this is true, imaging a black mage or white mage trying to farm. Black mages usually don't participate in the actual weapon skill chains. The have to wait for the DDs to pull off the chain and then magic burst on top of that. It is probably like trying to close a level three weapon skill chain. If you or any previous member messes up, no MB or level three skill chain.
Every job has its advantages and disadvantages. So many kitties here understand their favorite jobs and how to get the most out of them. The second most important thing is how to communicate your roll to the rest of the party. Then party leaders can put together effective plans to get the best effect. Waining about the nuking power of black mages is going to reduce the abilities of the party. This will not help anyone, include us damage dealers :!: