I'm working on developing a game mechanic into an OSR product.
The mechanic is my take on percentile systems.
Essentially, the DM sets the difficulty of the task, let's say its 50%. The Player's Ability Scores or Class then modify the difficulty. Let's say that I'm swing my sword at an orc, so I can either use my Strength (+10%) or Fighter Class (+20%). Fighter is the higher of the two and I use it and my modified chance to hit the orc is 70% on a d100 roll.
I plan on 4 Classes: Fighter (your skill weapons and tactics), Thief (the usual skills), Wizard (which translates into your Mana Points to power spells), and Cleric (which translates into your Faith Points spells).
At character creation you spread 20 points between the 4 Classes.
I also plan on the typical 6 Ability Scores (Strength, Dexterity, Constitution, Intelligence, Wisdom, and Charisma).
At character creation you spread 10 between the 6 Abilities.
When a task comes up you look at the appropriate Ability or the Class. You choose the Highest of the 2.
Thoughts?