Frankly, I think this is a brilliant idea. Following in his footsteps, I would like to propose a name change for the Holmesian Thief, where the archetype is Mr. Bilbo Baggins.
The reason I choose Mr. Baggins as archetype is because Tolkien casts such a long shadow over Holmes. Bilbo, more than any other character on Staple's list, fits into a Holmesian vision of D&D. So much so, that he implies that halflings can become thieves. The name I propose for the Holmesian Thief is the title that Gandalf gives Mr. Baggins in Tolkien's classic The Hobbit — Burglar.
Please note the definition of burglary in the Webster's Dictionary:
the act of breaking into a building esp. with intent to steal.Given that the Holmesian thief has the primary function of opening doors, I think this is eminently appropriate.
In light of this name change and its homage to the archetype of Mr. Baggins, I want to take a quick look and all of the burglar abilities in light of this archetype.
Open Locks: as I have noted before this ability does not impede other classes from opening locks. Everybody has a base chance to open doors of 2 in 6. This burglar ability, then, represents an extra and stealthy attempt to open doors for the adventuring party. If this attempt should fail, the party still has an opportunity to surprise whatever lies behind the door with a normal 2 in 6 chance to open a door.
Remove Traps: personally, this is my least favorite ability of any thief class. Keeping in mind Mr. Baggins, however, this ability can be re-skinned as a saving throw. Bilbo Baggins never really removed a trap, rather he was in the right place at the right time. Thus, remove traps can become a saving throw for when a player fails to figure out to how disarm a particular trap. Making the save means that the burglar is in the right place at the right time. Therefore, every class still has the opportunity to disarm traps. The burglar just has a better knack for it.
Pick Pockets: like remove traps, I am not a fan of this ability. Its primary purpose seems to be to steal from party members (something that more often than not can ruin the fun of an evening). Yet, Mr. Baggins does display some sleight of hand. Therefore, I think this burglar ability needs to be treated in much the same way as Remove Traps — as a saving throw. If a player fails to adequately describe the working plan on how to use sleight of hand, the burglar is allowed this saving throw. Again, this does not prevent other classes from trying — it just gives a burglar an extra chance not to fail.
Move Silently & Hide in Shadows: these abilities represent the burglar's affinity towards being sneaky (something Mr. Baggins was very good at). This is where I am willing to take a major departure from the traditional mechanics of the thief class. Everyone can be sneaky. Mechanically, this is represented by the surprise roll. Every class has a 2 in 6 chance of surprising an opponent. The traditional percentile rolls for move silently and hide in shadows divorce these abilities from the normal surprise roll. When a thief has the ability to backstab these percentiles seem necessary. The Holmesian thief, however, has no backstab ability. Therefore, move silently and hide in shadows serve no real mechanical purpose.
Rather than using these percentiles, I propose that a burglar has an increased chance to surprise. At first level this could start out at 3 in 6. Using the same progression pattern as hear noise, this would increase to 4 in 6 at 5th and 5 in 6 at 9th.
This surprise could be handled in one of two ways. The first would be to grant this surprise to everyone in a party that includes a burglar. The other is to allow the possibility for a burglar to have a round of surprise while the rest of the party does not. This latter approach treads closer to the literary source material. There were many times where Bilbo Baggins seems to have an opportunity to act while the rest of his party does not.
Hear Noise: humans have a 1 in 6 chance to hear noise. Demi-humans have a 2 in 6 chance. Burglars, whether human or no, begin the game with a 2 in 6 chance and get better as they increase in level. For the reason that it really needs no re-skinning or tweaking, this is my favorite of all the thieves' abilities.
I must say that given these few small tweaks, I am far more comfortable with the Holmesian Thief ( a.k.a. the Burglar) than I am with virtually any other version of this class. That is not something I was expecting to be able to say...