Noisy - a deep stall is something quite different from a full stall. If your instructor is talking about deep stalling I suspect him or her to be a little unsure of the difference (your still here so I assume you've not been deep stalling for real!)
The aim of the exercise is to learn the characteristics of a fully developed stall and to learn the recovery actions.
A further learning point is to recognise and recover from the onset of a stall.
To prevent wing drop with rudder is a rather dangerous way to expain what you are dealing with. Completely preventing a wing drop is exactly the same as picking a wing up with rudder - any yaw that develops will effectively be pro-spin.
It is much better to think of the phrase 'prevent further yaw' because without yaw the tendency to spin is very much reduced. Preventing a wing drop assumes that your rudder is powerful enough to overcome any autorotative tendencies right down to speeds below the stall - which it might be on the type you are flying now but might not be on the next type.
The aim of every exercise is to build airmanship. You must understand stalling but I feel that it is covered very badly indeed. All of the time is spent some way above the stall talking about 'sloppy control response' etc (which I think is very difficult to prove in some training types) then one rapidly decelerates into a hoofing great stall with a frantically pattering instructor trying to mention all of the salient features.
Very little time is spent around the high drag/high sink area close to the stall examining the fact that many training aircraft have comparitively little buffet as an onset warning. Very little is made of how one can spend time - at height - examining how quickly and delicately one can break a stall.
I feel that it is very poorly covered and we now see instructors who have a fear of stalling and a terrible understanding of the behaviour of an aircraft near the stall. The message is very much that there is stalling or flying and nothing exists in between. That, of course, encourages the view that stalling is a killer around the corner that will occur in the blink of an eye.