I think this is why I view fluid drills as being more important than static ones, the only way you can understand the balance of a motion is doing that motion over and over again till you learn where to adjust it.
I agree. The nice thing about training balance using rear leg side kicks, I find, is that there is so much motion packed into so short a time---from waaaay back to waaay in front, coming in from that outer back leg, close in to the body and then out again. If you can stay in good balance with that much of a radical change in momentum and body setup, you're going to develop a lot of balance control in general.