What about a pure caster spell or series of spells that lets them open locks?
Spell: Crack Lock
Lvl: 20
100 mana 4 second cast
35% chance to open lock
Enc, Mage, Necro, Wiz
Spell: Dissolve Lock
Lvl: 39
150 mana, 4 second cast
45% chance to open lock
Ench, Mage, Necro, Wiz
Spell: Destroy Lock...