As I previously mentioned, there are a plethora of ways to ‘fix’ thieves (beyond leaving them out of the game entirely). So I’ll show case a few, some from other versions of the game, and others from Bloggers or my own ideas.
As written, B/X D&D and, by extension, ACKS doesn’t figure attributes into thief abilities. A quick patch that works both with the core system and several of the options below involves using attribute mods on the thief abilities. This goes back to 1st Ed Advanced D&D so it has pedigree. The downside to it is that it makes attributes MORE important. I’ve come to realize that the reason you could create PCs back in the OD&D days rolling attributes 3d6 in order is because attributes played a very small roll in character effectiveness. They were nice bonuses to a few aspects of a character, but not mandatory. The main difference between a 9 INT wizard and a 18 INT wizard was the number of languages they knew… that’s it. But with Advanced, and every iteration of the game since, we’ve seen both a steady increase in what abilities do, as well as an increase in the perceived need for high numbers to ‘be effective’.
So, if you make abilities matter (which my gut from years of playing the later incarnations of D&D says you should, even though I like having them be less important) realize that unlucky players are further penalized. But, having said that, what’s the point of a high dex for a thief if you don’t make it count for abilities? Seems like there is little point to it at all (the normal dex bonus works for everyone and while the experience bonus is nice, it’s hardly a deal breaker).
Abilities and the skills they modify
Dex: Open Locks, Pick Pockets, Move Silently
Int: Remove Traps and Hide
Wis: Hear Noise
If you want to create custom classes with elven and gnomish thieves, further you can add:
Elf: +1 to Pick Pockets, -1 Open Locks, +1 Move Silently, +2 Hide in Shadows, +1 Hear Noise
Gnomes: +1 Open Locks, +2 Find/Remove Traps, +1 Move Silently, +1 Hide, +2 Hear Noise, -3 to Climb
Dwarves: +2 Open Locaks, +3 Find/Remove Traps, -2 Climb, -1 Read Language. Also their racial abilities, if many points are spent on Dwarf, gives flat proficiency bonuses, so their scores may be higher even than the above.
At a guess, for the new races in the Player’s Companion (and I’m just throwing these numbers out based on little knowledge):
Thrassian: -2 to Open Locks, -2 to Find/Remove Traps, +2 Move Silently, +2 Hide in Shadows, +3 Climb
Nobinar: -3 Pickpocket, +1 Read Language, +1 Find/Remove Traps, +1 Move Silently
Zaharian: -2 Climb, +2 Hide, +1 Read Language, +1 Move Silently