Let's start with the positive:
My letter is still making the rounds and I have been informed of discussions in several dojo about this important issue. It's good to hear that people continue to talk about it!
There has also been continuous support from kenshi, both publicly and in private, for which I am very grateful.
Therefore I want to take this opportunity to thank everyone for the overwhelmingly positive feedback! Arigato gozaimashita!

Unfortunately, there is also bad news.
Clearly, whatever support this issue has gotten, it has not been enough.
Hombu continues its silence, and at this point I do not have any reason to suspect that that is going to change. I suppose they expect the discussion to die down and thus the issue to go away for them – which is, of course, not what is going to happen.
In fact, it is getting worse: Older men with a lot of power will continue to hold down younger women with the aspiration, dedication, and ability to become part of the next generation of branchmasters, hopefully inspiring and continuing Kaiso's teachings and organisation.
I think it's fair to say that this will hurt WSKO in the long run, whether Hombu sees that or not – which is why I wrote the letter in the first place. No more, no less.

Which reminds me of a point that may sound unusual to most: Yes, I do exist. I am a kenshi at the Berlin shibu. My kenshi number is 616200549, if anyone cares to check. I participate in the online classes by WSKO, and am quite willing to discuss my personal decision to go public with the issue there or on any other medium.