I don't necessary agree 100% with your idea of DM requirements I do agree generally with what you are saying. I don't know that anyone ever masters diving, and believe continuing education should be a requirement for DM's. Maybe a good idea as you kind of touched on would be cross agency training.

I am a locksmith and similarly to a DM, I had to train and was tested before I could obtain my license however I must also take classes every year to keep my license. This keeps me up to date with current codes and procedures as well as new equipment and techniques. I would suspect that everyone here would agree that continuing education can only benefit everyone. There are costs involved for the classes and such, but they are really reasonably priced and is part of the cost of dong business.

I also don't take those classes from one teacher or agency. Most manufacturers offer classes on their products as well as training schools, association classes and more.

The need for more classes would also help the dive industry grow. More classes mean more dive conventions to offer classes. More certifications would also mean DM's could get paid more for their knowledge.