
Originally Posted by
Seraphor
Because their skills will be overpowered.
Because they wont have a rotation or skills interacting with each other, they wont have burst windows or anything that would resemble a rotation, which means each skill has to stand on its own. Each skill has to work efficiently and in isolation.
If it were BLM, then it means Fire IV would have to work without Astral Fire, without Enochian, without Umbral Hearts.
Once you add all those isolated, full powered abilities together, you get a whole selection of Fire IVs, Ahk Morns, Trick Attacks, Carve and Splits, Flares, Holys, TBNs, The Balance, Earthly Stars, etc. that you can use without build up or prerequisite.