I recently played a d20 based game (Call of Cthulhu, in fact), and found myself amused and frustrated by the fact that our 1st level characters, who were supposed to be experts in one field or another, did nothing but fail our skill checks for almost the whole session. My character was an 80 year old expert on the occult, and, due to unlucky skill rolls, I think I barely came up with a single piece of useful information about any of the occult mysteries we were confronted with! Given several thousand experience points (if level advancement still works that way in CoC d20, I don't know if it does...), and a careful allocation of skill points and selection of feats, I'm sure my character could gradually have worked his way up to being the expert which he conceptually was. But not at 1st level.
As a contrast, the other two game systems I've played recently are Savage Worlds and old-school D&D in the form of Labyrinth Lord. In Savage Worlds this phenomenon is not an issue at all. It's easy to create a beginning character who is very good at at least one useful thing. Meanwhile, in Labyrinth Lord / early D&D, the only character to have skills which require checks to be made is the thief. Characters of most classes can just do their thing -- fighters wear armour and wield weapons, magic-users cast spells, clerics heal wounds and turn undead. They may not have the most stupendous abilities at 1st level, but what they can do, they can do fairly reliably. Except the poor old thief, who can climb walls pretty well, but is really wiser to forget any of his other very cool abilities (like removing traps and moving silently) until he's at least 5th level.
And the mechanic for thief skills is exactly the system which was taken and used as one of the core elements of D&D 3rd edition -- skill checks -- leading up to my poor beleaguered occult 'expert'.
Alongside my recent re-experiencing of and reflections on the d20 system, I'd noticed that not a single player in my Labyrinth Lord campaign has expressed any interest in playing a thief. (Actually, one thief was rolled up, but he only had 1 hit point, so was sort of discarded.) I've always thought of thieves as a very cool class, but taking a look at their percentage chances of success at all the things they're supposed to be good at, I can understand their undesirability.
And then I read JB's post on auto-success thief skills. Brilliant stuff. As a player you totally want your character to be good at something, to be able to do something that no other character can do -- and all of the time! Not 14% of the time.
So, after a bit of reading around (including the Jovial Priest's very interesting take on the matter), here's what I'm thinking I'll offer to thief characters in my campaign. Not a rules change, but a simple re-interpretation of what the numbers mean and when the rolls are necessary.
Pick locks: Attempting to pick a lock takes 1 turn. If the roll fails, the thief is free to try again, spending another turn. However, time is often of the essence.
Find & remove traps: As per pick locks. The thief's find traps percentage can also be used to find secret doors, if it is better than the standard 1 in 6 chance.
Move silently: A thief can always move quietly. The % roll is only required when he needs to move completely without sound. Usually in the middle of a battle there is enough noise being made that this roll is not necessary to sneak up on an opponent who is unaware of the thief's presence.
Hide in shadows: Thieves are experts at hiding, and usually do not need to make a roll to hide from view, except in situations where shadows are the only concealment available. Even then, a thief can always successfully hide in sufficient shadow, given time to position himself (i.e. before the start of a battle). The % roll must be made in order to disappear into shadows in the middle of combat.
Climb walls: Thieves can climb normally without making a roll. The % roll must only be made when climbing up sheer surfaces such as walls or cliffs.
Pick pockets: No change.
Hear noise: No change.