Some seem to think diver training has been "dumbed down", but I agree with you. The current emphasis is on being in control rather than all over the place.
Most new divers swim with their feet down and head up. Why not? We like our head above our feet. Consequently, they always are light when swimming and/or heavy when they are not. Getting them into horizontal trim and teaching them how to breathe up or down rather than using the angle of the dangle, gives them a huge head start in mastering their buoyancy from the very beginning. No need for a 100 dives to figure it out, if it's taught from the beginning.
Swimming with your head is also a function or wanting to see where you are going. I know that sounds glib, but I find when carrying a camera, and taking pictures my profile is much more head up, than when I am not carrying a camera.
Your point though is valid. Getting people more horizontal means that when they stop swimming they don't immediately sink. I also find slowing people down, helps as well, they don't have the forward speed to counteract their negative buoyancy characteristics. Going slower, also suits me, I don't enjoy sprinting round a dive site, I generally meander slowly, I see more that way.
The dumbing down, is a circler conversation. I don't miss the fact that we now expect and use the Octopus in 'out of gas' incidents. I have done hundreds of ascents from 20m buddy breathing, and its no fun, even with a supposedly practiced and competent student who is expecting to do a rescue. Never mind trying to do it during a real incident. But I also do miss the confidence it developed in divers. My Advanced Nitrox course, my friend and regular dive buddy ended up buddy breathing on our stop, partly because we where bored, and the instructor was dealing with issues with other students. But mainly because we where extending my buddies gas, he was a 10litre cylinder, everyone else was on a 12litre (including me), and he was nearing his reserve limit. For us it was no issue, mind you, the instructor did have a double take when he noticed.