Yet another look at the thief and his job

 As so often happens, just as I zero in on The Way that I think will solve some glaring issue in the game, along comes a fresh insight or three to send me back to the ol' drawing board. I don't even recall precisely how this insight came to be in my head or whence it originated (it's drawn from more than one source, most likely), but here it is:

Fighters in D&D get better at fighting as they level up. They can hit better ACs more often, thus dealing more damage, and they gain hit points in good amounts (dice willing, of course!). This enables them to take on stronger and stronger challenges in combat, as is their job. A 1st-level fighter struggles against orcs and goblins, but eventually becomes mighty enough to make these nothing but light exercise, and to feel confident going up against trolls and dragons.

Magic-users in D&D get better at casting spells as they level up. They can cast more spells, they can cast better spells, and they can cast the same old spells with greater effect, increasing both their raw power and their versatility. Where the fighter can take on increasingly difficult challenges of the same type, the magic-user, as he levels up and gains new spells, is often able to overcome entirely new classes of obstacles that he couldn't have tackled at all before. Passwall, water breathing, even the relatively humble phantasmal force aren't just upticks in the character's effectiveness at things he could already do, they're literal game-changers.

The cleric does a bit of both.

And the thief... well, the thief gets better at facing pretty much the same old challenges. I'm pretty sure I've read, somewhere, some DM advice that suggests locks, traps, and other thiefly challenges may be made a bit easier or harder by applying bonuses or penalties to the thief's chance of success, but I'm fairly sure it wasn't in either Basic Set, where one would expect the basic universal principles of the game to be laid down. There is an oblique reference to penalties in Mentzer's Companion rules in a note regarding base percentages higher than 100%, but I think that's it. (Feel free to correct me if I'm wrong on this.) 

In any case, it's never codified in the same way that monsters are. Monsters have their own stats, especially Hit Dice, and it's explicitly stated that, in the dungeon, you can expect to encounter monsters with HD about equal to the dungeon level. The deeper you go, the tougher things get. 

Locks and traps and such, on the other hand, are pretty much what they are. They have no stats of their own, and I'm hard-pressed to think of anywhere I've even seen it hinted that they should become more fiendish as a party descends deeper into the mythic underworld. For the most part, and overwhelmingly so, a lock is a lock and a trap is a trap, whether on Dungeon Level 1 or Level 10, and the thief's chance of success is what it is. 

When a party of adventurers decides where to go delving for excitement and treasure, they can choose a level of difficulty, and their corresponding probabilities of success. If the 3rd-level fighters feel more comfortable with their odds of defeating 1st- and 2nd-level monsters, they can choose to stick to levels 1 and 2 of the dungeon. If they feel that they can manage a stiffer challenge, they can venture down to level 4 or 5. The poor thief, though, can't choose to explore a level where he has a comfortable chance to succeed at his job; a 3rd-level B/X thief has a 25% chance to open a lock on Dungeon Level 1 and a 25% chance to open a lock on Dungeon Level 10. And he sucks at it either way.

There's no reason at all why we couldn't rejigger the system, so that a thief will tend to encounter tougher locks and traps deeper in the dungeon, and easier ones nearer the surface, and calibrate things so he's reasonably competent at those of his own level. This actually lends itself well to a roll-over d20 scheme, rather than a roll-under d%, giving the thief a skill bonus according to his level, to be added to the skill roll and matched against an obstacle's difficulty. 

The big question we need to ask then is what should be the default chance of success for a thief vs. an obstacle of corresponding difficulty? It's impossible to make an objective comparison with the fighter class, but a quick-and-dirty comparison suggests the fighter has a little better than a 50-50 chance to defeat a monster of his own level. Monster attack rolls do scale up faster than the fighter's, but a fighter probably has better armor (even at level 1, a fighter likely has AC 4 or 5, compared to an orc's 6), as well as a possible Strength adjustment and magical equipment. It seems reasonable to infer a 60% success rate. Of course, even success often comes at the cost of some hit points, but then again, a thief is taking life-or-death risks too, since a chest or door lock may be trapped. So, at a cursory analysis, 60% feels good to me. That's a 9 or higher on a d20 roll. 

Before we go any further, we need to ask ourselves if we want other adventurers to have a chance at picking locks or finding and removing traps. If not, we just set the default difficulty rating to 10, and give a thief a +1 skill bonus per level, so a 1st-level thief trying to pick a 1st-level lock needs a 9. If we do want those other schmucks to have a chance at it, we can raise both the base difficulty and the thief's starting bonus, so the thief will be relatively better at what he does than said schmucks. Let's say, for instance, we raise the difficulty of a 1st-level lock to 12, and bump up the thief's starting bonus to +3. The thief still needs a 9, for a 60% chance of success, while the fighter or magic-user needs a 12, for a 45% chance. Still doable, but definitely inferior, and they'll never get any better. Either way, we scale up the difficulty by another point at each level, and the thief's skill by one point at each level of experience. 

This works a treat for locks and traps; after all, we can use the same rationale for them becoming more difficult the deeper one goes that we use for monsters. While some walls may be more difficult to climb, some noises harder to hear, and some situations less conducive to stealth, however, it strains belief a bit too much that these things should scale with dungeon levels. However, that's not necessarily a deal-breaker. For starters, locks and traps are probably the primary responsibilities for most adventuring thief characters, and will be encountered with the most regularity in dungeons. Secondly, the difficulty of those other things may not increase in step with dungeon levels, but the stakes generally will. The consequences of a 10th-level thief failing to sneak past a 10 HD red dragon are quite a bit more dire for the thief than failing to sneak past a couple 1-1 HD goblins when he was 1st level. Likewise, the consequences of failing to detect noise eight levels deep in the dungeon are likely to be much worse than missing that sonic clue on the entry level. It's also worth noting that you can still telegraph the difficulty of a challenge by other cues than dungeon level: for instance, let the player know that the floor around the dragon is covered in dry, brittle leaves, or the wall has a multitude of protruding blocks to use as hand- and foot-holds, and the player can thereby decide which his character is competent to attempt. It still allows the player agency, and makes skill improvement meaningful.

That's about as far as I'm going to take this line of thought for now, but it does seem like a worthwhile goal to flesh it out a bit more, especially with regard to the non-level-scaling challenges. (Should those skills improve on a shallower curve than locks and traps? Maybe... ) Perhaps I'll undertake that task one of these days in the near future.