Oh, yah, the reason actually makes sense with the character background, and "challenge" was probably too strong of a word--I just meant that the basic character concept would lead one to expect more skills, so the backstory really did need to cover that. (basically I took a concept for a standard character with skills B and dropped skills to E).
Anyway, found another way to address my question, and now am basically done the mechanical part, and just need to actually write down that backstory. I'm eager to see how this character works out ....