My clarinet history powers are slowly increasing ...
It hadn't occurred to me that some folks would dislike a horn playing a note properly. It does make sense. That


flat sounds sucky on a lot of clarinets, so there are probably some composers that recognize that fact and/or it might make blending in a group a bit more difficult. Good comment, Steve!
Standard Boehm clarinets have been hexxed by this since they were invented. (of course, we can just blame the flute).
Buffet (and Selmer / Leblanc) has moved the register vent, and changed it's dimensions/design over the years. From the late 50s, to the 60s, to the 70s when they moved it to provide a better Bb though losing a bit of color. Yamaha was the best neutral in their designs with a good throat Bb but early on were known for a lack of color in their tone.
The register vent really impacts the tonal quality .. I fiddled around with various lengths, and opening diameters and design a while back. Though I failed to document what I did. It was a quick exercise. I did this when I had a Buffet/Shreiber A clarinet which has this super long (both inside and outside) vent pip. I used it on a Bb, and conversely use a regular one on the A. Then played around with a few I removed from a couple misc. clarinets such as a Noblet and a few others laying around. A lot of engineering goes into the vent tube, design and placement.
Venting of the key has an impact too, as does how vigorously someone plays the note.
Since so many teachers are stuck on the "standard boehm" until the big makers synchronize on new keywork we seem to be stuck with it.
Just play a Full Boehm with the Long Bb (all the keys closed) and compare it to the throat Bb.
It's similar to playing a mid C on a sax with the 0x0-000 versus playing it as a side C x00-0|00 (or how ever that designation is). You can hear the tonal quality difference in most cases dependent upon embouchure/mpc used, etc.