I’m one of those that got the rushed OW course at a resort in HI. I’m sure starting out even after I received my cert, I looked not unlike what you witnessed. The interesting thing is watching other divers I recognized pretty quickly on my own that I had some work to do. The two absolute best things I did was take the PADI Refresher and Peak Performance Buoyancy certs. I am now AOW and Notrix cert. But these two courses are the ones that really made the difference. In Refresh, we worked on skills that I was able to pass in OW but not comfortable with (clearing a mask at depth). PPB made the largest difference. That is where I learned about ‘dangles’, learned that my inflator is not an elevator, etc. After that course, my diving is immeasurably more enjoyable. After that course, I properly weight myself, once at depth never even touch my inflator, and essentially glide around the bottom. In OW, I never learned the concept of using my lungs to control my depth. I was too busy worried about drowning. I personally strongly recommend PPB for new divers. For me it was like the continuation or fine tuning of what I learned in OW.
Morgan
I just did my SDI Advanced Buoyancy class (3 dives) today. Eye opening experience. Learned a bunch, but also a lot of hard work.