It would be smart if there were an organization like PolitiFact that accumulated important questions that the candidates haven't answered. For Clinton, an example might be "Where are the transcripts of the speeches you gave at Goldman Sachs?" For Trump: "Where are your tax returns." And you know I have a bunch of questions for Sanders.
It would also accumulate important questions for each candidate that no journalist has asked, and in doing so would help form a picture of conflicts that they have.