I dunno. The class d waveforms are pretty messy. Certainly there's more going on there on top of the 10 khz square wave than 500KHz switching. Of course you can take a look at some of the outputs of very popular tube amps Manley, et. al., and the output of a square wave input is barely recognizable as such. Of course many people love tube amps and more power to 'em. To each his own.
I remember my first decent stereo in the mid 70s - a Yamaha receiver, Yamaha wood base turntable, and Advent speakers. It sounded good or at least I thought so at the time. I had a friend who had the same Advents and a Technics reciever. His system had a good bit more bass than mine. The bass just thumped. He eventually blew the woofer one of his Advents. Looking back I'm sure Technics had done a bass boost at 100 Hz just like you hear in, say, a GM vehicle car stereo. Yeah, it gets your attention but ultimately is annoying and in any case doesn't sound right.
At this point I'm of the mind that I want my amplication to faithfully reproduce for better or worse the source input whatever that may be. And being of that mind, for now I'm sticking with Class A and A/B. A Krell amp for example does a good job of reproducing whatever is put into it. You can clearly see this in testing. There's little ringing and fuzz on the waveforms. Lot more heat and weight I agree but that's ok. I like the way bass sounds on a Krell.