BLM is a job that has never seen high play rates, and after the fiasco of DT on job changes for BLM, them adding even more instant casts is just the logical continuation of their reasoning. If they make it even more rigid than they made it already with the changes, the job will cater to even less people. Every caster in the history of XIV has slowly and steadily gained mobility over time. I don't see any reason why SE would suddenly backpedal on BLM, especially if instant casts are solving other problems like despair for them.