I think you hit it on the nose. Each person finds thier own way. That's the wonderful thing about this art. Exploration. People who say "no you're not doing it right because you feet need to be angled 3 inches more" are just nit-picking.
No, you are wrong. There is freedom. But before you graduate to be free you need to follow the lessons. There is a difference between the way Oguri and Nagato do things. But on the important points, they are the same. You may not know what those points are, but that does not mean that they are not there. And to say that you can just do anything and call it Bujinkan is just plain wrong. The angle of the kness can mean the difference between good taijutsu and bad taijutsu as well as needing a cane after 20 years of practice.
The devil is in the details. If you can't see the details, you need to get to a point where you can. If you do not understand something, you need to reach an understanding before you start fooling with it. And even if you
think you know it, odds are you do not.
The matter of second guessing Hatsumi is an interesting one. I personally think that we should be very cautious about the matter. You only need to look at my rants about the behavior of certain people in Japan to see my message that by the time you are told you are doing something wrong, it is too late. Someone once said that the modern day version of
hamon is to merely stop correcting a person when they make mistakes. I have seen something close to this when people will not make an effort to try what the teachers do. They get patted on the back and smiled at, and they are allowed to wallow in their ignorance while the teacher spends his precious time correcting and advising those that follow what he does. This results in a lot of westerners walking away thinking they are doing what the teacher wants them to do, when the truth is they are not worthy of the teacher's time.
When someone whom I am trying to follow the art of does something, that does not neccesarily mean that I should do the same. I may not be qualified yet, nor know the reasons for doing it. And it may be that they abandoned the aspect due to problems. A great example of that is how Takamatsu toughened his hands, only to lose a lot of their use in his golden years.
But when someone I wish to emulate does not do something or has done something and dropped it, I would want to be damn sure I knew why they did so before I fooled with it. It does not matter that they do not openly come out and forbid it, they also have not forbidden me to stick my hand in a meat grinder. I would want to know the reasons in and out before I decided that I knew enough to take it up.
And if you are teaching people using the name Bujinkan, it just seems natural to me to try to copy the ways and means of the top of the Bujinkan as much as possible. There is thinking for yourself. But part of that thinking should be the acknowledgement that we do not know all the answers. So there should be a certain amount of trust and just trying it their way. When we have mastered what they teach we will then be in a position to determine what is relevent and what is not. But unless someone has mastered the lessons, I can't see fooling with the teachings. The art is a whole, and the process is as important as the techniques themselves. If you are a student, you just need to do what they teacher lays out as he lays it out and put off exploring until you get your graduation papers. And if you are a teacher using the Bujinkan name, that goes double- if not more.