Raise SHOULD not be taken into account. rDPS increases are always available. Somebody doesn't always die. And no. Nobody takes BLM because their DPS is terrible. You shouldn't balance around something that you won't be using in all of your fights. It's not even a bad balance decision. It'd be as useless and dumb as balancing around palisade or dismantle. If the healers are competent the raid is competent, neither of your tools are used, but people with static rDPS increases or high personal DPS won't just lose these abilities as they are always applicable.