Umm, I guess I'll throw in a $.02 worth. I believe that within a particular system, all the katas should be taught, learned and practiced the same way. Now, with that being said, each student should develop his/her own understanding of each one. That may mean that the katas come out a little different in the end for each one, but everyone knows the same katas in the same way initially. (Did that make sense to anyone?) Take Toyama for an example. Two systems sprang from his teaching. The students he trained were trained in the same way, but went on later to interpret the training differently. (You shudokan stylists should get my meaning best here.) But when you get down to it, people would say "You've been trained by Toyama? Well then prove it, show me _____ kata." Then you would be expected to perform it like he taught it. (ie, not your "interpretation")