Not really a rules change/tweak, just a general suggestion:
Unless there are a lot of players (5+?) to represent a good selection of professions, be very generous in letting players nab bits and pieces from professions other than their own (as long as the concept still works and PCs don't end up too blandly similar). The niche specialization of professions is nifty, but when there are only a few players, each PC really needs to double up on key professional roles.
Beyond that:
I don't want to add a bunch more skills to DFRPG – there are arguably too many to begin with! – but to me, the following really feel like they belong:
- Navigation (Underground)
- Survival (Underground)
- Hidden Lore (Dungeons)
The first two are from
GURPS Underground Adventures, and spell a key difference between experienced underground
delvers vs generic adventurers. PCs without this experience might want to hire an underground "wilderness guide" who has the skills.
The third is my own simple idea: knowledge of where the world's dungeons are, what's in them, what famous delvers may have already raided them (or died trying), etc. This would be a fine skill for the PCs' agent back in town, who uses it to pick the next target and suggest preparations. Or PCs can gradually learn it on their own, eventually calling on their own knowledge to separate rumor from knowledge, choose targets for plunder, and prepare just what's needed... instead of having to rely on sketchy rumors in town, or locate a tavern drunk with a wild story and a map...