Actually Chris, I doubt if that sort of change will have much impact on koryu. I'm not saying they won't continue to evolve and grow, they will. They are living arts rather than fossils.
First though, the koryu don't change to adapt to students. Students change to adapt to the koryu, or they leave. So there is no push here for them.
I don't know of any koryu that is trying to become widespread and attempting to garner large number of students. The fastest growing koryu are some of the iaido ryu and Shinto Muso Ryu. None of them are bent on becoming hugely famous. They grow organically, and sometimes they even inhibit growth because they do not support the idea that if you are the only student in an area then you should teach. They are usually pretty tough about waiting to teach until you're really ready for the role.
Second, learning is always with a senior uke. You don't train with a junior.uke, whether it is jujutsu, kenjutsu or something else. This means rising students don't have a chance to try changing things until they are well and truly embedded in the system.
As koryu become more available, they still aren't becoming common. When someone can open a dojo, they often do, but the dojo stay small. Because of their insistence upon students changing to suit the ryuha rather than the other way around, they don't attract a lot of students. There is no commercial push to make the ryuha popular by changing it (unlike the guys at the IJF and judo).
Most of the koryu absolutely require wearing a hakama for at least part of their training. This isn't a ritual or cultural requirement, but a technological one. You really need all the cords and obi of a hakama to properly wear a katana for iaido practice. I've tried it with a number different set-ups on occasions when I didn't want to bother changing or a hakama wasn't available. It just doesn't work.
And then, koryu are all about maintaining the traditions. I think the community would be exceptionally clear in letting anyone who tried to jettison the traditions that whatever they might be doing, it isn't iaido or kenjutsu or whatever. The gekkiken guys and the chambarra folks have had to develop their own outfits and systems because everyone has been quite clear that they aren't doing kenjutsu or kendo.
Unlike Aikido, the koryu tend to have exceptionally strong organizations. They may have splits, but there are always guys at the top where the buck stops. There isn't room in the koryu for the kind of innovation we're talking about here.
There aren't really koryu organizations - well, I suppose there are, Kashima Shinryu has a federation - what really happens is, usually everybody is a direct student of the teacher. It isn't like here is your instructor for the evening, and a couple times a year you go to a seminar with one of the big guys and he throws your instructors around. For the most part. So when the head guy dies, the dojo often splinters because suddenly many of these people who have trained with each other for years (decades) can't get comfortable under the new guy if there is one. That's the opposite of a strong organization.
The basic deal with koryu is that they are based on ideals that were defined in a bygone era, and they could not be defined in modern times. So there is no question of whether there is a better way to do something. You maintain the tradition because the tradition is the art itself.
Aikido could be like this, but we can't even agree on what it is. If you find a teacher or an organization you like and stick to that, you are probably on the best track, but you have to stop looking around to see if somebody else is doing something cooler or more magical.