My experience is that you should ask the most honest questions you can think of asking. If the faculty don't like being asking, "Is there anything about your school that could be improved," then that could be a sign that the school is not open to criticisms of its programs.
On one of my interviews, I asked "This school looks pretty old, if I went here I would be paying top dollar for a run-down school." The interviewer responded, "don't judge a school by the condition of the walls, judge it by the quality of its faculty." Penn's preclinic lab is pretty old, but I can say that we had amazing instructors. I wouldn't trade my preclinical faculty for any fancy lab or computer system.