A mini-game killed my wife...
Fa real tho, I'm not a fan of Oblivion's mini-games. Not to say some minigames couldn't work better.
i'm also cool with skill requirements as long as they're not some stupid YOUR LOCKPICK MUST BE 50 TO OPEN THIS LOCK, EVEN IF YOU'RE AT 49 RIGHT NOW. the difficulty of the lock should be reflected in the lockpicking minigame itself, and in how forgiving it is to the player.
you should still be able to attempt to pick level 100 locks with very low skill levels, but at the same time they should be much, much less forgiving. the sweet spots should be TINY. your picks should break easily. as a player, if you manage to successfully pick such a difficult lock, you should feel genuinely proud of the accomplishment, and your skill increase should reflect that.
I still haven't played Fallout, but I'm curious now what the lockpicking is like. A good lockpicking mini-game, in my opinion, would be one where you try and follow a direction indicator on the screen, and move your joystick in time...kind of like grinding was done in a few skateboard games. However, if your skill was low and the lock was strong, it would be very hard to pick the lock with manual dexterity alone, and yet if your skill was appropriate, it would be almost impossible to fail. It's just a mechanic to make you feel like you are doing something, rather than simply pressing a button, like in Morrowind.
Of course, there should never be an "impossible" cut off, especially the "50 lock, skill 49" one mentioned above. But the larger the difference, the smaller probability of your character picking the lock. So if you sat all night and burned 25 lockpicks (I prefer Morrowinds, which degrade like weapons rather than snapping like twigs, although the occasional snap wouldn't be bad) you might eventually open a lock way beyond your skill (and, as above, receive a corresponding bonus.) I also believing characters should "learn through failure" at least a little bit. So even if you never open the lock, play with it long enough and you learn a thing or two. Of course, the longer you are picking a lock the more likely you are to get caught.