IMHO, the KD mechanism works best for skills that have multiple subcategories, like Profession or Craft. That said, while I like KD (and other oddball feats) and use them frequently, I can also see that basing expanded use of skills based on feats could be poorly viewed by players, given the 3.X Feat economy.I love that, and was going to do that, anyway, I just hadn't put it to paper yet, as it were. That is neater than anything I would have likely come up with--love it. Thank you!
I might actually base it on that skill, but I think I'm going to keep the bonus tied to the number of ranks possessed so that way, it's more a reflection of what you truly know versus depending on a roll that can vary wildly from one check to the next in terms of DCs based on situational variables.
With that noted, using a Feat to expand the uses of skills would require either doing a little work and expanding the umbrellas of the more focused skills, OR design the Skill-enhancing Feats cover multiple skills. An obvious candidate for the latter approach would be the “thiefly”/“roguish” skills. There might also be some overlap between such Feats.