What it boils down to is the student needs to maintain and build their own skills once they pass OW and AOW. Most people don't do that, they just dive and forget about any skills training they had and hope that they never have any problems.
That's all fine if nothing goes wrong, but when stuff goes wrong is when SHTF if they are unpracticed.
In all reality and knowing realistically what they could and would consider adding to the current training schedule would be a few more times of mask-off skills, reg clearing, and air shares. The way it is now they just have to demontrate is once and they pass. They should have to do it a half dozen times both in the pool and in open water. It wouldn't really add much more time (if any) and would at least establish a pattern and test of consistency with each student. Many are getting away with a one hit wonder by lucking out and pulling off a difficult skill once while they are on their best behavior. Let's see if they could do it 5 or 6 times in a row, that would be huge.
Practice makes perfect. Skills should also not be practised in the same manner as in the OW class (i.e., kneeling on a 20 ft. platform, OOA sharing facing your buddy, etc.). Practice mask clearing and OOA sharing while swimming which mimics more realistically what could happen in open water. Performing multiple skills builds confidence which helps stave off panic.
At the end of my OW pool training 40 years ago we did a "harrassment" style exercise where we had to replace a mask or reg removed by an instructor while swimming around the outer edge of the pool. In order to pass we could not break the surface. Some have suggested this would be counterproductive and lead to students panicking. However, we were only 2-3 ft under water and the instr's could easily pull us help if we got into trouble. I don't recall anyone complaining about it and no one panicked. This method incorporates multiple skills I mentioned above. How this type of training is done is important. Our skills were developed gradually over many pool sessions to get us there. Other skills we had to do was diving to the bottom of the deep end and put all our equipment on. Another was breathing off a tank valve (no reg) again at the bottom of the deep end. This involved removing the reg, breathing from the tank, and calmly putting the reg back in your mouth.