I really liked what I saw of RD100, but I think I hit my personal problem of having trouble reading through and absorbing systems from a PDF. I'm looking forward to the relaunch for streamlining, a better English translation, and a hardcopy version.
Back on the main topic, most of the systems I've seen that rely on backgrounds or careers as opposed to skills seem to use stats more heavily. Crossbreeding that with RD100's Traits and the character building system from Magic World, perhaps set baselines at a fixed percentage and then add stats based on the specific task? So Stefan would have something like Minor Noble 50%, +(Dex+Cha) or (Dex+Cha)/2 at a formal dance, +(Dex+Con) for a hunt, etc.