Initial ThoughtsFirst off, you should know that none of the classes exists exactly as it appears in the S&W Core. This is in large part a result of setting specifics. You can't have a Christian campaign without talking about what it really means to be a cleric, and that's naturally going to impact class description and certain game mechanics.
Second, I had been thinking of "sub-classes," like the ranger (Fighter), the scout (Thief), the astrologer (Magic-user), and others. Initially, I checked the S&W Complete rulebook, which contains certain of these specialists. However, they didn't really fit well—as described—into the campaign I envisioned, plus there were gaps that S&W Complete didn't fill.
Career PathsMy solution is to create "career paths" by taking a page from FrDave's Old School equivalent of prestige classes. The primary advantage is not having to create whole new classes, XP tables, spell matrices, etc. Simply take an existing class, bolt on specialised abilities, balance with some restrictions, and you have your sub-class. Level progression, hit dice, saves, and level limits remain intact—everything else is a matter of what feels right.
I want to stress this last bit. My natural inclination is to figure out some point value for each new ability and disadvantage, apply them so that they zero out, and declare that I have created a "balanced" sub-class. But I don't think that's the right approach.
Both Brendan and Reese correctly point out that a given prestige class really only makes sense when it's attached to a particular setting. That's not only true in terms of which sub-classes the setting supports, but also what those sub-classes can do. In other words, class should be defined by the setting, not the rulebook. If I used some point-value system to balance my career paths, it'd be the same as me telling you how to define a Druid or an Assassin in your campaign.
Instead, I'll just share my thoughts, and you can decide if it's too beaucoup for your campaign (or, just maybe, not enough beaucoup).
Something else about career paths that I should make clear: They aren't available during character generation. Again, I'm taking FrDave's suggestion and stating that PCs don't choose a career path until reaching 4th-level. I like the notion that levels 1-3 represent "apprenticeship" for the fledgling character. In setting-specific terms, ascending to 4th-level is the equivalent of attaining journeyman rank, and thus possessing sufficient "general" knowledge of one's field to specialise in one aspect of it. In game terms, this makes it easier to roll up new characters, because you're not bogging down char-gen with a lot of "prestige class" details.
RacesPretty much all human, all the time, at least as PCs go. Which brings up two caveats:
- Demi-humans may show up, but as monsters, and in the Norse Mythology style. So you might encounter dwarfs who turn themselves into a pike and hide out in deep pools, or elves in the light, dark, and swart variety (which may be dwarfs as well, depending on the translation?).
- There may be human variants that can mimic demi-human abilities (e.g., a dwarf's find stone traps or an elf's find secret doors). I won't necessarily map demi-human abilities to human sub-races, but there will be specialised mannish folk.
Next Up, Christian Clerics
Listening To: Orange Goblin, Frequencies From Planet Ten