I think it'd be better if....
there were 3 templates, for +1, +3, and +5 variants. Then the quality of metal used provided a number of charges to the item (thus breaking from the standard lockpick used by nwn). It would require a new misc item be made with a OnUse property and custom scripts instead of the oine shot items already in game.
Thus I could see...
Simple Lockpick Template (Effective +1) : Copper DC10, Bronze DC15, Iron DC20, Steel DC 25
Standard Lockpick Template (Effective +3) : Copper DC 15, Bronze DC 20, Iron DC25, Steel DC30
Complex Lockpick Template (Effective +5) : Copper DC 20, Bronze DC 25, Iron DC30, Steel DC35
The effects of the material would provide a greater number of charges along the lines of...
Copper - single use
Bronze - 3 charges
Iron - 5 charges
Steel - 10 charges
The one thing I would not like to see is the templates sold in the smith shops. They would be better suited to shops like the shady merchant in Tigan's, or some npc in the drain.