G, you're exactly right, a horse should move correctly because the rider is riding it correctly. Some people (like the individual at the expo) go to alternative methods for their own reasons...not sure how to fix/train, don't want to take the time, or think they are correcting the problem the right way.
Myself, we do everything natural at our barn. We have 4 shoes on our horses -just plain old regular shoes to protect her feet on trails. But in the winters we just work barefoot in the arena learning to correct the horse and make them walk properly naturally.
There are excersizes you can do with your horse to aid in their walking ability (pacing them out, hills, trails...etc), everyone has their own opinions on what is right and what works, and with different opinions comes the fact every horse is different. You'll have to work through it and find what works best for you, but like I said, the idea with the shoes on the front and not the back is to stop pacing but i dont think your boy needs pads, heavier shoes, or shoes on just the front. Just corrections when he goes out, working on your blanace (as that is huge in this breed) and also they need to build the muscles and know what gait you want them to be in ...training really. It's a joint effort on horse and rider :) and he definitely has the talent to get consistent with his movement!