It is possible for manufactutrers to reduce distortion and breakup through the use of different cone materials. In the case of KEF Meta they put a maze shaped pad behind the tweeter to reduce back wave reflection. Car audio guys do the same thing on door mounted woofers to reduce the magnitude of the back wave.
Probably does some good but likely subtle.
The biggest change for the Meta series is the smoother, tapered frequency response. Voicing changes through crossover tweaks. Made a big difference.
The new series do seem to minimize brightness and metallic overtones, possibly at the expense of detail from what I have heard during demos.
Is there embelishment in the Meta marketing? You bet there is.