This subject hits one of my buttons.
1. DM needs rebranding. Passing a DM course mean you've reached the entry level of dive pro. It doesn't mean you're suddenly a super hero
2. DM course are highly profitable for dive centres, especially when they laughingly turn over a course in 10 days. I personally believe it takes 3 months of mentoring, to expose a candidate to most of the situations they will face in the real world.
Maybe the course is 2 part. Initial cert where you're able to be a certified assistant and then Pt 2 where they're mentored and assessed with real customers and real dives
3. It should be an entry requirement for DM's that Tec 40 has been complete (insert your agency's Intro to tech course) far too many dive pro's struggle with the rudimentaries of dive theory
4. Make it easier to fail a student. Too many candidates expect the cert to be awarded just from attendance (the bare minimum at that) They want the bragging rights without putting in the work and gaining knowledge.
5. Require that Instructors take a further qualification before being allowed to teach DM. Too many Instructors take combined DM/OWI course and have zero experience guiding dives with real customers. How can they pass on experience to the students if they have non themselves
I think the above appraisal is pretty accurate and that the recommended adjustments would improve diving the world over.