of Thieving skills and the common man

I know a lot of people don't allow the thief class into their game. This stems mostly from the fact that thieving skills seem to cover things anyone should be able to to. In my campaigns, I usually handle this with a 1d6 roll for normal players, while thieves get to do that and the normal percentile roll in most cases. Listed below are the rules I use.

• Picking pockets: 1d6. 1 = success, 6= the character was noticed. Thieves and Bards use the standard % roll and aren't able to use the 1d6 roll.
• Open Locks: Non-standard lockpicks: 1= success 6 = item breaks or lock becomes jammed. Actual Lockpicks = 1-2= success 6= item breaks or lock becomes jammed. Thieves use their standard % roll for both standard and non-standard picks, with only a roll of 00 causing a jam or broken pick.
• Find/Remove Trap: Any character actively searching for a trap has a 1-in-6 chance of finding a trap that is very well hidden. For traps that are not so well hidden, the chances raises to 1-in-3. Rogues get to use the 1d6 roll first, and additionally get to use their Find/Remove Traps roll immediately after to reflect that thieves have had greater practice and training to look for this sort of thing. Additionally, in my games, I dispense with the rolling for the Removal of Traps. The player has to tell me how the character is disarming the trap. ONLY MAGIC MAY DETECT MAGIC TRAPS unless there is some sort of glyph or other physical component to the trap that a person could sense.
  
• Move Silently: Everyone is able to move silently to some degree. The character makes an AC check(like an ability check, but with the character trying to roll under his AC). The character may only do this while carrying no more than a medium load, and his movement is reduced to 1. Rogues get to use this option OR the standard % roll which will allow them to move at greater speeds.
• Hide in Shadows: A character may only attempt this while carrying no more than a light load. A character who successfully hides may not move at all. Small or smaller characters have a 1-in-2 chance of hiding successfully provided there is something for them to hide behind/within/what have you. Medium creatures have have a 1-in-3 chance, while large creatures have a 1-in-6. Rogues are able to use the same method as everyone else OR their % roll to grant themselves the ability to move while hidden, so long as some form of "cover" exists(shadows, some sort of actual visual obstruction, etc.).
• Detect Noise: Everyone has a chance of this, exactly as described in the DMG. Rogues just have a better chance because of their training.
• Climb Walls: As Discussed in the PHB under Climbing
  
• Read Languages: This skill is one that has always presented problems to me. Why do rogues get this skill, but mages, who practically live and die by the written word, do not? Instead of allowing this skill to make any rogue into a polyglot, I am instead interpreting it to mean that the character may crack codes/ciphers. any character has a 1-in-6 chance of translating any single letter or word(DM's choice depending on the difficulty and complexity of the code/cipher). A character may only do this once for any given letter/word in the message, until he gains some sort of assistance(library, or even a successful check on other words/letters in the code). A rogue on the other hand, may do the % roll before he checks each individual word, and once when he gets through to determine the whole message. This skill is available ONLY to people who are able to read/write the given language.