The earliest core Save or Die is the Phantasmal Killer, and mass SoD is Circle of Death. Wouldn caster versatility be reduced before getting these spells?
SoLs are concerned with ending the encounter, not instantly killing the target. After being blinded a monster is almost completely useless and can be dispatched at your leisure. Most Big Five characters have a wide variety of means to kill the disabled foe (such as summoned monsters or animal companions), or another party member can coup-de-grace or sneak attack.
