Way back when, I made a list of reasons why someone might choose to practice a sword art. The last reason was that we might want to be part of, and help perpetuate, a rich cultural and historical tradition.
Tradition is very important to some people, to the extent that it seems as though they chose to do the martial arts they do, completely on the basis of how old it is, or how "pure" its lineage is. Perhaps they started with a popular "modern" martial art like kendo or iaido, but were drawn to the ryuha that formed the basis for these arts.
On the other hand, some people don't care about tradition at all. If, for example, iaido was something that was invented in 1982 in a basement, it wouldn't make a difference to them, because it is their practice of iaido in the here and now that is important to them.
The problem, I think, is when people try to have their cake and eat it too. There are some people out there who have invented their own style, or heavily modified an existing style to suit their own way of thinking, and yet claim that it is "traditional samurai swordsmanship" or something. This just seems dishonest to me, as well as egotistical. They are saying, in effect, "I know more about how swordsmanship should be done than the people I learned it from. But I don't expect you to take my word for it. Let's pretend this was all invented by sword masters hundreds of years ago, and passed down to me through secret channels."
This is not to deny that, in the process of learning an art, everyone adapts some things to make the art their own. But I think it is right that we should emulate our teachers as well as we can.
To give you a personal example: I'm a big guy, about 195 cm, (6'5") 110 kg. My teacher, Kim Taylor, is also a big guy. One of our very influential Sensei was Haruna Matsuo Sensei. He was perhaps 5'4" and rather slight. While neither Kim nor I could ever move in exactly the same way that Haruna Sensei did, Kim (being a lot stronger) comes much closer to copying him. With my flabby physique, I just sort of flop around in a pale imitation of them both. Physical reality means that my iai is not the same as my teachers' iai ... but I try, and trying is key.
Deliberately introducing changes to techniques, however - particularly where those changes concern the speed and feeling of how a technique is done, or fundamental things like where the enemy is, what he is doing, and how you respond - twists the original tradition.
I went to an art exhibition in Tokyo a few months ago. The featured artist, Ai Wei Wei from China, is a very conceptual artist who deals in ideas. One of his artworks featured three photographs, taken in quick succession, of him holding a Tang dynasty (618 - 907 CE) vase, him releasing the vase, and the vase shattering on the ground.
Another one of his works was to take another ancient vase, and then paint the Coca Cola emblem on the side of it.
I don't claim to fully understand the meaning of this artwork, but obviously he is commenting on our role as curators to the past. On one hand, a 1300-year-old vase is something to be treasured and preserved simply because it is old, rare, and connects us with a past which we can never revisit. But on the other hand, he makes a valid point, I think - these objects exist in the here and now, and who has the right to say that an intact vase is more beautiful than a collection of shards, or that writing Coca Cola on the side of a vase doesn't make it more relevant to our modern era?
Mr Ai's work is controversial, and there must be many people who see it as nothing short of vandalism. I can understand this point of view, certainly.
When it comes to the martial arts, I don't have anything against people creating new styles, because doing that does not effect extant styles. My problem arises, I think, when these new styles - by virtue of being flashier or more slickly promoted - draw people away from older arts to the point where the older arts die out. Or, another danger is when people lie about the art's origins, and teach hundreds or even thousands of students a false version of history.
You might not like Mr Ai's art; you might think shattering a priceless vase is mindless and meaningless destruction. But at least he documented it, and took credit for what he did. The same cannot be said for some modern martial artists.