The "extreme" horns have progressed more than alto & tenor since the MkVI age, bari and sop mostly under the initiative of the Japanese manufacturers. This includes keywork advances, but also ease of response and intonation (specially on soprano).
Of course, most current oriental stencils include those design features (eg "Yanagisawa copy"), for 1/3 of the price.
Some unique features remain unique, like the anti-sticky-G# on Keilwerths.