I think that the argument that BLMs are bad on progression should be dropped tbh, everyone in prog needs to learn the fight, as of now with the possibility of keeping up enochian forever we aren't that punished unless we ourselves fail completely.
As for the managing our our CDs and movements CDS, well that is something that everyone does to min max the dmg on a fight as such I don't see that much of a difference, what does make a difference is a static knowing the strength of a BLM and not beign oblivious to some facts.