If you think BLM is bad then what about BRD? Outside of Barrage every 2 mins it's almost useless. Plus terrible distance penalty, something mages don't have. And yet nobody complains about it.

They nerfed because BLMs had 'unnaturally high win rate' on jp servers. Fire IV in AF3 is 504 potency, 630 with Enochain and Raging Strikes damage bonuses, 2-3 in a row can kill anyone. If their spells are spammed without interruption, that will make BLM in a constant burst mode, something other jobs can do only once in 90-120 seconds. With AOE crowd control options it makes them overpowerful.

Some BLMs successfully adapted with Thunder/Sharpcast procs gameplay, which is not as bursty but much more SMN-style mobile, maybe you should try it out.