[quote=Gyson]The point is spellcasting allows players to trivialize the Lockpicking skill and get around durability loss penalty when blasting past locks.
So, either make locked doors and containers immune to magic, or come up with a penalty that is on the same level of durability loss. You can require a weapon be equipped to cast a spell, it doesn't have to be a staff, and then have that weapon take durability damage. durability loss
I agree that there's a balance issue, but overhauling how magic works just to fix a minor mechanic like lock picking is like flooding the basement to kill some rats.
Neverwinter Nights 2 had a workaround to this problem where using offensive magic to open chests would destroy its contents. Combine this with maybe making some doors immune to magic would be an infinitely better system, in my opinion, than messing with how magic works elsewhere in the game.
