Kathryn, I can see your point, but the principle thing that a class in any art must address for it to be functional, is to familiarise you with application of techniques against an oponent who does not want you to succeed. If training drills are always compliant, then you have no way of knowing if the techniques stand a chance of working for you when the target isnt playing along in the name of learning.

This does not mean it has to be 100% balls-to-the-wall full contact, it just has to be realistic in intent- both yours, and your oponents, and there has to be freedom for 'unscripted' responses to various methods of attack and defence in a free flowing environment.
Don't let the door hit ya' where the good lord split ya'