Horizontal pulling exercises such as bent-over rows, dumbbell rows, seated rows, and machine rows mainly train the action of shoulder extension.
However, to strengthen horizontal shoulder abduction you need to add exercises like wide-grip rows, face pulls, dumbbell rear-delt flyes, or machine rear-delt flyes. The single-arm rear delt flye, shown in the video, also fits the bill.
With squats, fear is often the limiting factor. Part of us is afraid that a big weight will flatten us like a pancake and make people want to pour syrup onto us. Heavy Supports will cure that fear.
That title makes you think of a graceful, fluid movement, like that of a ballerina performing a perfect pirouette. Well, dumbbell deadlifts just ain't ballet.