Perhaps you can give us some more vivid examples. I, for one, thrive on actually "seeing" what people are talking about, so maybe you can show what you mean visually somehow.
Say we have 10 questions/problems in our database, and course A uses the 1st five and course B uses the 2nd five.
Would the questions that populate the database be marked somehow, such that we know their source? If not, then I do not understand what you mean, exactly, by the comparison of different teachers and/or curriculums (if this is, indeed, what you meant).
From what I do understand, though, it sounds interesting. I'm all for aggregating knowledge and making it more accessible where possible.