It's worth noting that you could make opening the door what rewards the experience rather than picking the lock. If you found the key, bashed it open, or convinced someone to open it for you, you get experience. If you convince a party of enemies not to attack, you get experience equal to what they'd be worth if you killed them. If you kill them afterwards, you get no experience, because you already 'defeated' the encounter. The experience being awarded is for completion of a goal, as you suggest in your edit, rather than a particular action or kill that yields the experience.
That was exactly my point.
Which is precisely why I insist that the system should ideally reward the goal (i.e. "enter the room X") rather than each of the various alternate means to reach for it (i.e. lockpicking, finding a key, getting the key through dialogue or pickpocketing, disarming the trap in front of the window and jumping from there, etc).
Take the tomb robbers you find in the starting ruins. Currently you can have a minor exp bonus for scaring them away and STILL freeze to turn based mode and kill them to double the exp reward.
Now, putting aside that this MAY have other minor implications in the final game (i.e. maybe Gimblebock or whatever he's called is someone you could meet again later on in the game if left alive) I think that ideally there should be a FIXED amount of exp for getting rid of them, regardless of how, and NOT exp reward on top of it for killing them.
