I was thinking of ways to improve BLMs mobility and quality of life, and progging Ultimate. Right at the beginning, you're AoE'ing down those plumes until Garuda decides to vanish, but maybe some plumes are alive? So I switch targets before she vanishes to a plume, but what happens when said plume dies? So does my spell...

This is a problem for ALL targeted AoE spells, but it's something the devs could fix. Not all enemies become 100% untargetable by spells upon death. Why not allow Flare, Foul, and other AoE casts to continue casting, even though the target died (so long as the spell was started while they were alive.) In exchange, the diminishing effect should remain. The spell would do nothing to already defeated enemy, and then deal the standard percentage less potency to each additional target.

Really, the worst thing to BLMs is interrupting our spells. This type of change would be a step in the right direction. Hope the devs consider it Thanks.