While I like blue switches, I don't think they are a good fit for the Kinesis keyboard. With flat keyboards every key press feels the same, but with the contoured, for the top row keys you have to press by pushing your fingers forward, for the bottom row you have to pull them toward yourself, etc, so each row needs a slightly different kind of finger movement, and the significant tactile resistance of the blues would make it harder to type in my opinion. Browns are ok since their tactility is minimal, but I have found linear switches to be the best option for me. I love my Advantage LF with red switches. I have occasionally revisited my older keyboards with browns, and always go back to reds!
Anyway, this is personal preference; I'm pretty sure a small minority of users might prefer blues on it, but I agree with the demand would not be enough.
BTW I love the click sound, it really helps me avoid bottoming out so I always have it on.
Hmm, I'm wondering, now that the LF is mainstream and sold both direct and by retailers, what's the percentage of LF vs the base Advantage model sold these days ?