One practical point that seems to not have been brought up in this discussion, is whether teachers are capable of addressing some of the major theological or philosophical questions which plague their students. Aspiring teachers are often untrained in these areas. While some teachers have taken undergraduate or graduate courses in these areas, many have not.
Perhaps it is time to consider whether preparation in these areas should be mandatory for aspiring middle school and high school teachers. Just as we expect gemara teachers to have many hundreds of hours of serious gemara learning under their belts, and for teachers of Tanach to be experts in their field, those who address the most serious questions which plague our students, need to know of what they speak.
Pesach Sommer