Generic? Are you serious?
Those "generic" subjects are what this election is all about ....
The questions are going to be far less general than the subjects, I hope. The problem occurs when a candidate lacks the knowledge to answer and diverts to personal attacks and name calling. This is where the moderator should step in. If he doesn't, then the other candidate's rebuttal will follow suit and it will continue through the debate.
I disagree ... if the candidate wants to diverge ... let her.
The people will decide.
It's not the moderator's job to dictate the information they want fed to the American people. Give the moderator a stopwatch and a pointer - and tell him to shut up.
It actually is the moderator's job to keep things on topic, perhaps you are not familiar with the time honored format of a formal political debate. The rules of order are there for the sake of the audience/voters, not the candidates. Any well reasoned position can be successfully argued in a debate format, unfortunately for Trump the rules of debate quickly show when someone is not arguing a well reasoned position.
As a matter of fact, I AM familiar with the "time honored format of a formal political debate".
For instance, I am familiar with the fact that presidential debates were NOT moderated until 1960 - hardly a "time honored" approach.
The "rules" for debate allow the moderator to decide when something the candidate says is out of bounds. Of course, this can, and is, regularly abused. (See Candy Crowley's disgraceful actions - or, perhaps, Becky Quick, Carl Quintanilla, or Matt Lauer). It's as simple as tilting the wording of a particular question (ask Quintanilla) or injecting your own opinion into the discussion (ask Candy Crowley) or making false accusations in the form of a question (ask Quick), or simple incompetence (ask Lauer).
The real "time honored" format is to allow each candidate to make an opening statement, and then allow candidates to ask their opposition questions. It worked for Lincoln-Douglass - Clinton really shouldn't need to be fed softball questions by the liberal press.