Teaching practical classes are one of the best things they could teach kids. Here are some things I was taught in public school, starting in Jr. high, that helped me when I became an adult.
Nutrition, balanced meals
How to cook
How to make a piece of clothing from scratch, using a pattern and how to operate a sewing machine.
How to make a living budget
How to balance a check book, banking
How to drive a car
How to take care of a car
Making a book shelf
How to use household tools
How to take care of a baby/small child
Some kids today can't even do something as simple as addressing an envelope. It's mind blowing to me how unprepared kids are. They have no imagination either.
Another thing I've seen lacking is how one approaches a problem or project. Too many are clueless about how to go from concept to finish. They don't even know where to start using basic logic.