gedunk once bubbled...
Yes to the above.
My brothers kids will have good trim and buoyancy control before they get their cards, bank on it. And like i said, they will develop excellent trim and buoyancy control if they continue to work at it.
Where i part ways with you is the supposition that all divers i taught before spending more time on trim, are "bad divers." The ones who have stayed active, generally are very good divers. The term "bad diver" is quite subjective IMO. To me a "good diver" stays in trim while swimming and can maintain depth control +/- a foot or so in the column, vertical or horizontal. An "excellent diver" can do all the above, keep depth control to the foot and maintain horizontal trim, swimming or not. I realize your definitions are probably different. Are the divers i'm teaching today better for the time spent on trim, yes they are. Are the students that came before them, bad divers? Not in my opinion.
I am not defending the $99 weekend class or instructors that don't spend enough time on skills, i have never agreed with that and fight it every week with the competition. But its not black and white like some of you allude. There is plenty of room between meeting agency standards and teaching all DIRF type skills. Many of us are smack-dab in the middle of the above, meeting agency standards and injecting skills such as trim into the class.
From my observation, students taught this way thrive if they are serious about the sport. The students who end up diving once or twice a year in Coz will never keep their skills up, GUE, Padi or other.