Scholars roll is great for blms since their set bonus is based off conserve mp, making it way better then caster's roll in the long run, who wouldn't want to do better dmg over having a shorter casting time and recast. All the rolls are dependant on whos in the party.
I disagree, in Abyssea at least. BLM are largely there for Yellow proc. The faster they can get those spells off the better. IF you are nulled, you want your recast time down as well. If I'm in the magic proc party as COR, its Casters and Evokers until proc then Wizards/Evokers. SCH roll is definitely second tier with Healers roll these days. Might be worth it with Brewing, but wth the massive refresh of Brew, I think the Wizards/Warlocks combination would just as easily get the job done.