Drag-step question

One of my longtime students contacted me with a question about how to do a drag-step. When he did a drag-step he brought both feet together, then stepped. His instructor told him that was wrong and that he should only bring his feet half-way together before the step-out. So, he wanted to know, which way was right?
Actually, they're both right. It's important to keep in mind that basics, as they are taught, are reference moves. They act as a start pointing point, used to transmit the methods and angles of delivery, power principles, etc. Then you tailor the move to suit, as long as it doesn't depart the framework set down that makes Kenpo what it is.
In the real world (and in some of the techniques) you see variations in the application of the moves based on what is needed to make things work. Sometimes that short version of the drag-step is necessary because you just don't need to go that far. Other times you need to change the drag-step into a crossover to cover ground. The standard techniques illustrate the situation when you would do one or the other (that's why we shouldn't alter the standards when we teach them, so we don't lose those examples).
Our guy's teacher said you don't want to bring the feet all the way together because you could get your feet kicked out from under you. Sure could. A good Judo person would absolutely try to do that to you. If that's what you're dealing with then you must be careful how you place you feet and shift your weight. But if you need to get closer and the danger is not present, or is minimal, go ahead and bring your feet together. Just remember that Ed Parker said you need to keep your head at the same height or even a bit lower in order to prevent the rise in the center of gravity that is so inviting to someone to take you off balance. (Consider also that if you are punching them at the same time they are less inclined to do so.) He liked the analogy of a compass, as you recall.
On the other hand, former world champion kickboxer Bill "Superfoot" Wallace says that as you slide forward your feet should come together and your center should rise to enable you to lighten up the kicking leg and get some height and momentum. It worked for him and many schools today successfully teach the Wallace kicking method.
So who is right?
I think everyone here is correct, given the appropriate situation and application. Teach the drag-step as a reference movement by bringing the feet together for full range of movement. It's just like teaching a punch from the chamber, which also teaches full range of movement. As you improve you condense the movement but still get the desired result. In Kenpo we keep the head at the same level for the basic movement and then do the different applications in the techniques.
A basic is a basic, a fundamental move. Use them as a place to start the discussion.