Listen to suggestions made and be willing to make changes when they are justified. Most drop-outs, because of dissatisfaction with organizational structure, can be avoided. Poor Teaching is the bane of many Sunday schools. This is preventable and should be dealt with kindly but firmly in every circumstance. However, we need to be sure that everyone has a clear understanding of what poor teaching is.
Poor teaching is the result of apathetic attitudes, poor preparation and lack of commitment.
Good teaching does not require a specified education or even superior Biblical knowledge. I have sat under excellent teaching that was peppered with poor grammar and mispronounced words. Encourage your teacher to attend teacher training sessions available to them, provide good resources for study and preparation and set your standards high. Never be afraid to study by those high standards. Talk with those teachers who do not comply and pray diligently about the situation.