Two thoughts:
1 : You get out of the martial arts what you put into it. Though it is true that many martial arts use kata to teach principles, not techniques, it is up to the individual to understand that. It is all too easy for someone to simply collect techniques and fight by rote, rather than breach an understanding of why they are doing what they do. To that effect, there are those that would use the Kihon Happo as a series of techniques, and never really understand the underlying principles.
This next part directly relates to Techno's comments. For these type of people, I think that the type of attacks are VERY relevant. If a technique collector only ever practices against a long, straight punch, that is all they will ever be able to defend against. They don't seek the principle and they don't get it. In light of that, I will go out on a limb and suggest that moderrn American fast food mentatality creates an overwhelming majority of technique collectors. Perhaps it makes sense to "modernize" a system by introducing "realistic" and "modern" attacks. You and I know that if you master a principle, you don't have to train for every attack under the sun because you can dynamically apply. But if you have no clue about the principle, then maybe you need to train against every attack?
2 : This is related to Don's comments about stress and kata training. I agree, however we also have to consider that unlike the majority of modern martial artists, traditional japanese martial artists were warriors that had to repeatedly use their skills on the battlefield. If they had little experience with adrenaline and stress management, they would soon become indoctrinated in it with their first military engagement. So in the koryu I think it would be reasonable to assume that these warriors had a level of stress training that many modern practitioners never experience.
I know that most will not agree with me on this next part, but I also use this as a basis for why I feel that resistant partner training and sparring is important. The people who founded and taught the martial schools of old did so with direct battlefield experience. They did not need rubber suits of armor or sparring pads to gain actual hands on combat experience. Their lives were frought with danger already. But today that is not the truth with most of us, and we kid oursleves if we believe that we are trained in the same way as warriors of old, because we are missing that key element of application. However there have been modern developments (ie. Kano etc.) that take us a step closer.
