For my case specifically, my raid leader(s) told me (and the other Mage) not to use AoEs because it's a DPS loss on bosses to bother with it. This pretty much applies to anything with AoE (Megaera Wyrms, Day Phase Twins, and Lei Shen Ball Lightnings), and to just leave it to the other clothies (SPriests and Warlocks).
Should I actually need some long-term AoE, I'd use Flamestrike, but the problem is that a portion of its damage relies on the enemies staying there after using it, AND that they stay in that area, on top of having a cast time and a cooldown. Flamestrike simply has too many negatives tied to it for it to be of any real use outside of a couple niches (as you said, Pre-cast on Ji-Kun)
- Cast Time (used to be instant)
- Cooldown (used to be spammable)
- Not all damage is instant (enemies must stay in the area/stay alive long enough to get the full DPET out of it)
*- Slows enemies
* Is sometimes a bad thing, depending on fights, but I'm not actually counting it; just pointing it out.
I don't want Flamestrike removed, I just want it to not be garbage and back to its former Cataclysm glory. I also want Blastwave back and not tied to a garbage version of Flamestrike.