I may not like MNK, but I know they're not useless; after all, they can solo-silence the entire Turn 2 if they're good enough

A BRD that doesn't (need to) sing is more or less useless and the spot better filled by any other DPS, for example (except on Titan, though stacking BRD there is still unnecessary, since melee have it about as easy as BRD in those fights and do more damage).