I never had a an issue with this and it was further reinforced when I switched over to point based system like Fantasy Hero and GURPS. There an adventurer that 100 points can kick the crap out of a 200 point non-adventurers simply because the 200 point character has all his points in skills like blacksmithing.
When working on the Boxed set the solution was easily handled by the fact that D&D 3.0 NPC classes of Common, Aristocrat, Expert, etc. A 10th level Expert is likely to come up on the short end when facing even low level adventurers.
So when translanting my Majestic Wilderlands into Swords & Wizardry (a clone of OD&D) I need to represent this aspect of my world. Likely Jeff Rients hits a home run with his Hedge Mage post.
The key innovation is not the class but the idea that levels are based on years of experience. Unlike D&D 3.0 version where NPC classes are weaker, this makes non-adventurers fundmentally different than adventurers. Not only different but in a way that makes them very unappealing to play as PCs. And to me it feels more like D&D than the 3.0 solution.
So why worry about this at all? Why just use the referee's magic wand and just make it up. For two reasons. First many of the adventures in the Majestic Wilderlands revolves around interacting with normal society rather the monsters found in dungeon crawls or wilderness expeditions. Because of that I like to have a variety of mechanics than what a 1D zero level man offers. Second my endgames in the Majestic Wilderlands often involves the players hiring a variety of specialists and other unique types that are not normal adventurers. Using this idea allows me to give these NPC more variety in terms of abilities.
In conjunction with the Skill System I outlined here. I have a method of creating a variety of NPCs with interesting abilities without just have create them from scratch every time.
The level of a non-adventuring class is based on the number of years they have spent working their profession. This can be modified by having a high or low prime requisite score.
Prime Requisite Modifiers
3 +3 years
4 to 5 +2 years
6 to 8 +1 year
13 to 15 -1 year
16 to 17 -2 years
18 -3 years
Craftsmen specialize in a single skill. Nearly any of the skills in the Tasks section can be chosen. The Skill’s ability modifier becomes the class’s prime requisite. It is also a limit on the maximum skill level the Craftsman can learn.
Prime Attribute: The Skill’s attribute.
Hit Dice: 1d6
Armor: Leather and shield
Weapons: Dagger, Short sword, Short Bow, Light Crossbow, Club, and Staff.
Level Years HD Saving Skill Required
Throw Lvl Attribute
1 0 to 1 1 17 1 10
2 2 1 17 3 11
3 3 to 4 1 17 4 12
4 5 to 6 1 17 5 13
5 7 to 11 1 17 6 14
6 11 to 15 1 17 7 15
7 16 to 23 1 17 8 16
8 24 to 31 1 17 9 18
9 31 to 39 1 17 10 18
10 39 to 50 1 17 11 18
11 50+ 1 17 12 18
Blacksmithing would be a STR based skill.
Carpentry would be a DEX based skill
and so on.