B/X - Thief Skils for Everyone

Recently, I've been reading the rules for Lamentations of the Flame Princess, and I'm quite enamored with the Specialist class (Raggi's version of the Thief). Instead of using the standard table, the system gives you 1-in-6 chance to succeed on any of your skills (Hear Noise, Move Silently, Hide in Shadows, etc...) and 4 points to increase the 'pips' on those skills. So, from the beginning, you get some say in what you specialize in, rather than just being a thief. Each level thereafter, you gain 2 more points to increase your odds of success.

One grievance about the Thief I've heard voiced by grognards and zoomers alike is that the Thiefs existence codifies these skills as only being accomplish-able by that class (some think the class and skills are pointless altogether). Later editions 'fixed' this by broadening the skill system for all classes and just giving Thieves/Rogues more skill points. However, I think I have a solution that empowers all characters without stepping on the Thief's toes.

Start with the B/X Thief Skills (Climb Surfaces, Find/Remove Traps, Hear Noise, Hide in Shadows, Move Silently, Open Locks, Pick Pockets) and some general mechanics (Searching, Find Food/Hunting). Every character has a 1-in-12 chance of success provided they have the right equipment (e.g. lockpicks) or their armor doesn't inhibit their chances (Climbing or Moving Silently in Plate Armor).

Now, instead of allocating all your experience towards leveling up, characters can put some toward these skills. By 'spending' 600 experience (half the exp needed to level up a Thief), you can increase your skills by 4 pips. For instance, you could put all 4 into Climb surfaces, for a 5-12 chance of success, or putting 1 pip in four different skills for 2-in-12 chance of success. Spend another 1200 experience for 4 more pips, 2400 for 4 more, etc... If a skill reaches 12-in-12, instead roll 2d6; rolling two 6s is a failure.

As for Thieves, you could keep them as they are with their Roll-Under percentile table, or you could adopt the LotFP specialist rules and keep the skill mechanics universal, regardless of class.