Here Ryan talks about Perception. It got me thinking about skills, the thief, and D&D in general.
I think that for any skill based system You can combine the negotiated approach with the mechanical approach by limiting the times you need to roll.
For example if there is a chest covered by garbage then the player "says I will undercover the garbage" they will find the chest.
If however it is a jewel in that pile. Then I would have a roll because it may be missed despite the player digging through it.
If the player insist on standing at the door and looking around the room. Then you would roll for the chest in the garbage (the garbage is piled up unusually) but there would little or no chance to spot the jewel.
This the approach GURPS takes to avoid incessant rolling of skills. And I apply this technique to any skill based system.
Now for older editions of D&D what I would do it make sure that everybody can to a base series of actions. (Perception, climb, stealth, etc).
The thief class would sacrifice combat ability in order to be good at something else. I wouldn't even call it a thief class. More like a rouge class. A thief would be one of the many rogues that sacrificed combat ability to so something better.
In the thief case, the thief is better at things involving dexterity. A thug in contrast would be focused on strength, and charisma to rule his gang. Other combinations could be made for Conmen, Merchant Adventurers, etc.
The other classes are not prevented doing the skill based stuff. But because they are focused on fighting, praying, or spells they never are as good as the rogue.
The problem with the original Thief that it implies that only the thief can do certain things. Just only the fighter get the high HD and good to hit bonus. Only the magic-user get to cast wizard spells.
If they instead laid out how everybody could climb, perceive, jump, etc, and gave thief a bonus then I think everyone would have a better feeling about the thief class or in my class the rogue class .
I did think of another class that I would consider a rogue, the Mountebank. In my mind a Mountebank is someone who lost some fighting ability but gained the ability to cast a small number of Wizard's spells. Throw in hiding, and sleight of hand/pickpocket I think that would be a good addition to the mix.