But there is no way there will ever be a class D amp that is truly state of the art until someone does every thing to the nth degree
This is correct, but even more important for Class-D to be able to do to over take the best linear amps, is that they cannot come close to doubling their wattage for each halving of impedance from 8ohm to 4ohm to 2ohm for those speakers that are very hard to drive eg: Wilson Alexia
And the even bigger problem to get rid of, is the phase shift in the audio band that the output filter creates to rid the output of most of the switching frequency noise https://ibb.co/Bs1tJ7d . And the only way to do this is to take it all up higher x 3 (switching frequency and filter) to 1.5mhz or more instead of 600khz.
ONLY then, could it be called to be better, than or equal to, the very best liner amplification.
Cheers George