On a Sorc, you want spells that do 1 of 2 things
Kill Baddies (Fireballs and the like)
Keep the Sorc from getting bushwhacked (Invisibility goes under this category)
All those nifty utalitarian spells like Identify should be ignored, they eat up slots, and your party's wizzy can handle those.
OTOH, you could make an Ultimate Summoning Sorc.
