Every interview I have experienced, seems more like free consulting than a job interview. Granted I appreciate the non-traditional questions, i.e. what are your strengths and weaknesses, but the questions seem to be solving their problems rather than conveying my long term skill sets.
What if candidates could charge for their time and expenses, if they are not offered the job? Do you think this would change the interview landscape? Think of it as "spec" work. No one likes, or should, do work for free. If you build it, it has value. If you educate on problem solving, it's the same thing.