Cure serious/mortal wounds are totally pointless in P&H: they do nothing more than the basic spells, are higher level... and cost more mana!!!
In PWMang I have upgraded those 2 spells to Cure Wounds (5-12d10 depending on charlevel) and Healing (100), and renamed Healing to Extra Healing to balance HP healed/mana used more effectively. Maybe those should be upgraded in vanilla Mang too...